net: allow to delete a whole device group

With dev group, we can change a batch of net devices,
so we should allow to delete them together too.

Group 0 is not allowed to be deleted since it is
the default group.

Cc: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 38 insertions, 0 deletions

diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index e7695104dbf0..b96ac2109c82 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -1836,6 +1836,42 @@ errout:
         return err;
 }
 
+static int rtnl_group_dellink(const struct net *net, int group)
+{
+        struct net_device *dev, *aux;
+        LIST_HEAD(list_kill);
+        bool found = false;
+
+        if (!group)
+                return -EPERM;
+
+        for_each_netdev(net, dev) {
+                if (dev->group == group) {
+                        const struct rtnl_link_ops *ops;
+
+                        found = true;
+                        ops = dev->rtnl_link_ops;
+                        if (!ops || !ops->dellink)
+                                return -EOPNOTSUPP;
+                }
+        }
+
+        if (!found)
+                return -ENODEV;
+
+        for_each_netdev_safe(net, dev, aux) {
+                if (dev->group == group) {
+                        const struct rtnl_link_ops *ops;
+
+                        ops = dev->rtnl_link_ops;
+                        ops->dellink(dev, &list_kill);
+                }
+        }
+        unregister_netdevice_many(&list_kill);
+
+        return 0;
+}
+
 static int rtnl_dellink(struct sk_buff *skb, struct nlmsghdr *nlh)
 {
         struct net *net = sock_net(skb->sk);
@@ -1859,6 +1895,8 @@ static int rtnl_dellink(struct sk_buff *skb, struct nlmsghdr *nlh)
                 dev = __dev_get_by_index(net, ifm->ifi_index);
         else if (tb[IFLA_IFNAME])
                 dev = __dev_get_by_name(net, ifname);
+        else if (tb[IFLA_GROUP])
+                return rtnl_group_dellink(net, nla_get_u32(tb[IFLA_GROUP]));
         else
                 return -EINVAL;