net_device: add support for network device groups

Net devices can now be grouped, enabling simpler manipulation from
userspace. This patch adds a group field to the net_device structure, as
well as rtnetlink support to query and modify it.

Signed-off-by: Vlad Dogaru <ddvlad@rosedu.org>
Acked-by: Jamal Hadi Salim <hadi@cyberus.ca>
Signed-off-by: David S. Miller <davem@davemloft.net>

4 files changed, 26 insertions, 0 deletions

diff --git a/include/linux/if_link.h b/include/linux/if_link.h
index 6485d2a89bec..f4a2e6b1b864 100644
--- a/include/linux/if_link.h
+++ b/include/linux/if_link.h
@@ -135,6 +135,7 @@ enum {
         IFLA_VF_PORTS,
         IFLA_PORT_SELF,
         IFLA_AF_SPEC,
+        IFLA_GROUP,             /* Group the device belongs to */
         __IFLA_MAX
 };
 
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index d971346b0340..68a4627b74f5 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -75,6 +75,9 @@ struct wireless_dev;
 #define NET_RX_SUCCESS          0       /* keep 'em coming, baby */
 #define NET_RX_DROP             1       /* packet dropped */
 
+/* Initial net device group. All devices belong to group 0 by default. */
+#define INIT_NETDEV_GROUP       0
+
 /*
  * Transmit return codes: transmit return codes originate from three different
  * namespaces:
@@ -1153,6 +1156,9 @@ struct net_device {
 
         /* phy device may attach itself for hardware timestamping */
         struct phy_device *phydev;
+
+        /* group the device belongs to */
+        int group;
 };
 #define to_net_dev(d) container_of(d, struct net_device, dev)
 
@@ -1844,6 +1850,7 @@ extern int		dev_set_alias(struct net_device *, const char *, size_t);
 extern int              dev_change_net_namespace(struct net_device *,
                                                  struct net *, const char *);
 extern int              dev_set_mtu(struct net_device *, int);
+extern void             dev_set_group(struct net_device *, int);
 extern int              dev_set_mac_address(struct net_device *,
                                             struct sockaddr *);
 extern int              dev_hard_start_xmit(struct sk_buff *skb,
diff --git a/net/core/dev.c b/net/core/dev.c
index 7741507429f4..2b85d4ae981f 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -4572,6 +4572,17 @@ int dev_set_mtu(struct net_device *dev, int new_mtu)
 EXPORT_SYMBOL(dev_set_mtu);
 
 /**
+ *      dev_set_group - Change group this device belongs to
+ *      @dev: device
+ *      @new_group: group this device should belong to
+ */
+void dev_set_group(struct net_device *dev, int new_group)
+{
+        dev->group = new_group;
+}
+EXPORT_SYMBOL(dev_set_group);
+
+/**
  *      dev_set_mac_address - Change Media Access Control Address
  *      @dev: device
  *      @sa: new address
@@ -5678,6 +5689,7 @@ struct net_device *alloc_netdev_mqs(int sizeof_priv, const char *name,
         dev->priv_flags = IFF_XMIT_DST_RELEASE;
         setup(dev);
         strcpy(dev->name, name);
+        dev->group = INIT_NETDEV_GROUP;
         return dev;
 
 free_pcpu:
diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index a5f7535aab5b..09062b07bf7f 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -868,6 +868,7 @@ static int rtnl_fill_ifinfo(struct sk_buff *skb, struct net_device *dev,
                    netif_running(dev) ? dev->operstate : IF_OPER_DOWN);
         NLA_PUT_U8(skb, IFLA_LINKMODE, dev->link_mode);
         NLA_PUT_U32(skb, IFLA_MTU, dev->mtu);
+        NLA_PUT_U32(skb, IFLA_GROUP, dev->group);
 
         if (dev->ifindex != dev->iflink)
                 NLA_PUT_U32(skb, IFLA_LINK, dev->iflink);
@@ -1265,6 +1266,11 @@ static int do_setlink(struct net_device *dev, struct ifinfomsg *ifm,
                 modified = 1;
         }
 
+        if (tb[IFLA_GROUP]) {
+                dev_set_group(dev, nla_get_u32(tb[IFLA_GROUP]));
+                modified = 1;
+        }
+
         /*
          * Interface selected by interface index but interface
          * name provided implies that a name change has been