rtnetlink: Honour NLM_F_ECHO flag in rtnl_newlink_create

This patch pass the netlink header message in rtnl_newlink_create() to
the new updated rtnl_configure_link(), so that the kernel could reply
unicast when userspace set NLM_F_ECHO flag to request the new created
interface info.
Suggested-by: Guillaume Nault <gnault@redhat.com>
Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
Reviewed-by: Guillaume Nault <gnault@redhat.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net/core/rtnetlink.c

@@ -3312,11 +3312,13 @@ static int rtnl_group_changelink(const struct sk_buff *skb,
 
 static int rtnl_newlink_create(struct sk_buff *skb, struct ifinfomsg *ifm,
 			       const struct rtnl_link_ops *ops,
+			       const struct nlmsghdr *nlh,
 			       struct nlattr **tb, struct nlattr **data,
 			       struct netlink_ext_ack *extack)
 {
 	unsigned char name_assign_type = NET_NAME_USER;
 	struct net *net = sock_net(skb->sk);
+	u32 portid = NETLINK_CB(skb).portid;
 	struct net *dest_net, *link_net;
 	struct net_device *dev;
 	char ifname[IFNAMSIZ];
@@ -3370,7 +3372,7 @@ static int rtnl_newlink_create(struct sk_buff *skb, struct ifinfomsg *ifm,
 		goto out;
 	}
 
-	err = rtnl_configure_link(dev, ifm, 0, NULL);
+	err = rtnl_configure_link(dev, ifm, portid, nlh);
 	if (err < 0)
 		goto out_unregister;
 	if (link_net) {
@@ -3579,7 +3581,7 @@ static int __rtnl_newlink(struct sk_buff *skb, struct nlmsghdr *nlh,
 		return -EOPNOTSUPP;
 	}
 
-	return rtnl_newlink_create(skb, ifm, ops, tb, data, extack);
+	return rtnl_newlink_create(skb, ifm, ops, nlh, tb, data, extack);
 }
 
 static int rtnl_newlink(struct sk_buff *skb, struct nlmsghdr *nlh,