drivers/net/macvtap.c

   1 #include <linux/etherdevice.h>
   2 #include <linux/if_macvlan.h>
   3 #include <linux/if_tap.h>
   4 #include <linux/if_vlan.h>
   5 #include <linux/interrupt.h>
   6 #include <linux/nsproxy.h>
   7 #include <linux/compat.h>
   8 #include <linux/if_tun.h>
   9 #include <linux/module.h>
  10 #include <linux/skbuff.h>
  11 #include <linux/cache.h>
  12 #include <linux/sched/signal.h>
  13 #include <linux/types.h>
  14 #include <linux/slab.h>
  15 #include <linux/wait.h>
  16 #include <linux/cdev.h>
  17 #include <linux/idr.h>
  18 #include <linux/fs.h>
  19 #include <linux/uio.h>
  20
  21 #include <net/net_namespace.h>
  22 #include <net/rtnetlink.h>
  23 #include <net/sock.h>
  24 #include <linux/virtio_net.h>
  25 #include <linux/skb_array.h>
  26
  27 struct macvtap_dev {
  28         struct macvlan_dev vlan;
  29         struct tap_dev    tap;
  30 };
  31
  32 /*
  33  * Variables for dealing with macvtaps device numbers.
  34  */
  35 static dev_t macvtap_major;
  36
  37 static const void *macvtap_net_namespace(struct device *d)
  38 {
  39         struct net_device *dev = to_net_dev(d->parent);
  40         return dev_net(dev);
  41 }
  42
  43 static struct class macvtap_class = {
  44         .name = "macvtap",
  45         .owner = THIS_MODULE,
  46         .ns_type = &net_ns_type_operations,
  47         .namespace = macvtap_net_namespace,
  48 };
  49 static struct cdev macvtap_cdev;
  50
  51 #define TUN_OFFLOADS (NETIF_F_HW_CSUM | NETIF_F_TSO_ECN | NETIF_F_TSO | \
  52                       NETIF_F_TSO6)
  53
  54 static void macvtap_count_tx_dropped(struct tap_dev *tap)
  55 {
  56         struct macvtap_dev *vlantap = container_of(tap, struct macvtap_dev, tap);
  57         struct macvlan_dev *vlan = &vlantap->vlan;
  58
  59         this_cpu_inc(vlan->pcpu_stats->tx_dropped);
  60 }
  61
  62 static void macvtap_count_rx_dropped(struct tap_dev *tap)
  63 {
  64         struct macvtap_dev *vlantap = container_of(tap, struct macvtap_dev, tap);
  65         struct macvlan_dev *vlan = &vlantap->vlan;
  66
  67         macvlan_count_rx(vlan, 0, 0, 0);
  68 }
  69
  70 static void macvtap_update_features(struct tap_dev *tap,
  71                                     netdev_features_t features)
  72 {
  73         struct macvtap_dev *vlantap = container_of(tap, struct macvtap_dev, tap);
  74         struct macvlan_dev *vlan = &vlantap->vlan;
  75
  76         vlan->set_features = features;
  77         netdev_update_features(vlan->dev);
  78 }
  79
  80 static int macvtap_newlink(struct net *src_net, struct net_device *dev,
  81                            struct nlattr *tb[], struct nlattr *data[],
  82                            struct netlink_ext_ack *extack)
  83 {
  84         struct macvtap_dev *vlantap = netdev_priv(dev);
  85         int err;
  86
  87         INIT_LIST_HEAD(&vlantap->tap.queue_list);
  88
  89         /* Since macvlan supports all offloads by default, make
  90          * tap support all offloads also.
  91          */
  92         vlantap->tap.tap_features = TUN_OFFLOADS;
  93
  94         /* Register callbacks for rx/tx drops accounting and updating
  95          * net_device features
  96          */
  97         vlantap->tap.count_tx_dropped = macvtap_count_tx_dropped;
  98         vlantap->tap.count_rx_dropped = macvtap_count_rx_dropped;
  99         vlantap->tap.update_features  = macvtap_update_features;
 100
 101         err = netdev_rx_handler_register(dev, tap_handle_frame, &vlantap->tap);
 102         if (err)
 103                 return err;
 104
 105         /* Don't put anything that may fail after macvlan_common_newlink
 106          * because we can't undo what it does.
 107          */
 108         err = macvlan_common_newlink(src_net, dev, tb, data, extack);
 109         if (err) {
 110                 netdev_rx_handler_unregister(dev);
 111                 return err;
 112         }
 113
 114         vlantap->tap.dev = vlantap->vlan.dev;
 115
 116         return 0;
 117 }
 118
 119 static void macvtap_dellink(struct net_device *dev,
 120                             struct list_head *head)
 121 {
 122         struct macvtap_dev *vlantap = netdev_priv(dev);
 123
 124         netdev_rx_handler_unregister(dev);
 125         tap_del_queues(&vlantap->tap);
 126         macvlan_dellink(dev, head);
 127 }
 128
 129 static void macvtap_setup(struct net_device *dev)
 130 {
 131         macvlan_common_setup(dev);
 132         dev->tx_queue_len = TUN_READQ_SIZE;
 133 }
 134
 135 static struct rtnl_link_ops macvtap_link_ops __read_mostly = {
 136         .kind           = "macvtap",
 137         .setup          = macvtap_setup,
 138         .newlink        = macvtap_newlink,
 139         .dellink        = macvtap_dellink,
 140         .priv_size      = sizeof(struct macvtap_dev),
 141 };
 142
 143 static int macvtap_device_event(struct notifier_block *unused,
 144                                 unsigned long event, void *ptr)
 145 {
 146         struct net_device *dev = netdev_notifier_info_to_dev(ptr);
 147         struct macvtap_dev *vlantap;
 148         struct device *classdev;
 149         dev_t devt;
 150         int err;
 151         char tap_name[IFNAMSIZ];
 152
 153         if (dev->rtnl_link_ops != &macvtap_link_ops)
 154                 return NOTIFY_DONE;
 155
 156         snprintf(tap_name, IFNAMSIZ, "tap%d", dev->ifindex);
 157         vlantap = netdev_priv(dev);
 158
 159         switch (event) {
 160         case NETDEV_REGISTER:
 161                 /* Create the device node here after the network device has
 162                  * been registered but before register_netdevice has
 163                  * finished running.
 164                  */
 165                 err = tap_get_minor(macvtap_major, &vlantap->tap);
 166                 if (err)
 167                         return notifier_from_errno(err);
 168
 169                 devt = MKDEV(MAJOR(macvtap_major), vlantap->tap.minor);
 170                 classdev = device_create(&macvtap_class, &dev->dev, devt,
 171                                          dev, tap_name);
 172                 if (IS_ERR(classdev)) {
 173                         tap_free_minor(macvtap_major, &vlantap->tap);
 174                         return notifier_from_errno(PTR_ERR(classdev));
 175                 }
 176                 err = sysfs_create_link(&dev->dev.kobj, &classdev->kobj,
 177                                         tap_name);
 178                 if (err)
 179                         return notifier_from_errno(err);
 180                 break;
 181         case NETDEV_UNREGISTER:
 182                 /* vlan->minor == 0 if NETDEV_REGISTER above failed */
 183                 if (vlantap->tap.minor == 0)
 184                         break;
 185                 sysfs_remove_link(&dev->dev.kobj, tap_name);
 186                 devt = MKDEV(MAJOR(macvtap_major), vlantap->tap.minor);
 187                 device_destroy(&macvtap_class, devt);
 188                 tap_free_minor(macvtap_major, &vlantap->tap);
 189                 break;
 190         case NETDEV_CHANGE_TX_QUEUE_LEN:
 191                 if (tap_queue_resize(&vlantap->tap))
 192                         return NOTIFY_BAD;
 193                 break;
 194         }
 195
 196         return NOTIFY_DONE;
 197 }
 198
 199 static struct notifier_block macvtap_notifier_block __read_mostly = {
 200         .notifier_call  = macvtap_device_event,
 201 };
 202
 203 static int macvtap_init(void)
 204 {
 205         int err;
 206
 207         err = tap_create_cdev(&macvtap_cdev, &macvtap_major, "macvtap",
 208                               THIS_MODULE);
 209         if (err)
 210                 goto out1;
 211
 212         err = class_register(&macvtap_class);
 213         if (err)
 214                 goto out2;
 215
 216         err = register_netdevice_notifier(&macvtap_notifier_block);
 217         if (err)
 218                 goto out3;
 219
 220         err = macvlan_link_register(&macvtap_link_ops);
 221         if (err)
 222                 goto out4;
 223
 224         return 0;
 225
 226 out4:
 227         unregister_netdevice_notifier(&macvtap_notifier_block);
 228 out3:
 229         class_unregister(&macvtap_class);
 230 out2:
 231         tap_destroy_cdev(macvtap_major, &macvtap_cdev);
 232 out1:
 233         return err;
 234 }
 235 module_init(macvtap_init);
 236
 237 static void macvtap_exit(void)
 238 {
 239         rtnl_link_unregister(&macvtap_link_ops);
 240         unregister_netdevice_notifier(&macvtap_notifier_block);
 241         class_unregister(&macvtap_class);
 242         tap_destroy_cdev(macvtap_major, &macvtap_cdev);
 243 }
 244 module_exit(macvtap_exit);
 245
 246 MODULE_ALIAS_RTNL_LINK("macvtap");
 247 MODULE_AUTHOR("Arnd Bergmann <arnd@arndb.de>");
 248 MODULE_LICENSE("GPL");