drivers/net/macvtap.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 #include <linux/etherdevice.h>
   3 #include <linux/if_macvlan.h>
   4 #include <linux/if_tap.h>
   5 #include <linux/if_vlan.h>
   6 #include <linux/interrupt.h>
   7 #include <linux/nsproxy.h>
   8 #include <linux/compat.h>
   9 #include <linux/if_tun.h>
  10 #include <linux/module.h>
  11 #include <linux/skbuff.h>
  12 #include <linux/cache.h>
  13 #include <linux/sched/signal.h>
  14 #include <linux/types.h>
  15 #include <linux/slab.h>
  16 #include <linux/wait.h>
  17 #include <linux/cdev.h>
  18 #include <linux/idr.h>
  19 #include <linux/fs.h>
  20 #include <linux/uio.h>
  21
  22 #include <net/net_namespace.h>
  23 #include <net/rtnetlink.h>
  24 #include <net/sock.h>
  25 #include <linux/virtio_net.h>
  26 #include <linux/skb_array.h>
  27
  28 struct macvtap_dev {
  29         struct macvlan_dev vlan;
  30         struct tap_dev    tap;
  31 };
  32
  33 /*
  34  * Variables for dealing with macvtaps device numbers.
  35  */
  36 static dev_t macvtap_major;
  37
  38 static const void *macvtap_net_namespace(const struct device *d)
  39 {
  40         const struct net_device *dev = to_net_dev(d->parent);
  41         return dev_net(dev);
  42 }
  43
  44 static struct class macvtap_class = {
  45         .name = "macvtap",
  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 net *macvtap_link_net(const struct net_device *dev)
 136 {
 137         return dev_net(macvlan_dev_real_dev(dev));
 138 }
 139
 140 static struct rtnl_link_ops macvtap_link_ops __read_mostly = {
 141         .kind           = "macvtap",
 142         .setup          = macvtap_setup,
 143         .newlink        = macvtap_newlink,
 144         .dellink        = macvtap_dellink,
 145         .get_link_net   = macvtap_link_net,
 146         .priv_size      = sizeof(struct macvtap_dev),
 147 };
 148
 149 static int macvtap_device_event(struct notifier_block *unused,
 150                                 unsigned long event, void *ptr)
 151 {
 152         struct net_device *dev = netdev_notifier_info_to_dev(ptr);
 153         struct macvtap_dev *vlantap;
 154         struct device *classdev;
 155         dev_t devt;
 156         int err;
 157         char tap_name[IFNAMSIZ];
 158
 159         if (dev->rtnl_link_ops != &macvtap_link_ops)
 160                 return NOTIFY_DONE;
 161
 162         snprintf(tap_name, IFNAMSIZ, "tap%d", dev->ifindex);
 163         vlantap = netdev_priv(dev);
 164
 165         switch (event) {
 166         case NETDEV_REGISTER:
 167                 /* Create the device node here after the network device has
 168                  * been registered but before register_netdevice has
 169                  * finished running.
 170                  */
 171                 err = tap_get_minor(macvtap_major, &vlantap->tap);
 172                 if (err)
 173                         return notifier_from_errno(err);
 174
 175                 devt = MKDEV(MAJOR(macvtap_major), vlantap->tap.minor);
 176                 classdev = device_create(&macvtap_class, &dev->dev, devt,
 177                                          dev, "%s", tap_name);
 178                 if (IS_ERR(classdev)) {
 179                         tap_free_minor(macvtap_major, &vlantap->tap);
 180                         return notifier_from_errno(PTR_ERR(classdev));
 181                 }
 182                 err = sysfs_create_link(&dev->dev.kobj, &classdev->kobj,
 183                                         tap_name);
 184                 if (err)
 185                         return notifier_from_errno(err);
 186                 break;
 187         case NETDEV_UNREGISTER:
 188                 /* vlan->minor == 0 if NETDEV_REGISTER above failed */
 189                 if (vlantap->tap.minor == 0)
 190                         break;
 191                 sysfs_remove_link(&dev->dev.kobj, tap_name);
 192                 devt = MKDEV(MAJOR(macvtap_major), vlantap->tap.minor);
 193                 device_destroy(&macvtap_class, devt);
 194                 tap_free_minor(macvtap_major, &vlantap->tap);
 195                 break;
 196         case NETDEV_CHANGE_TX_QUEUE_LEN:
 197                 if (tap_queue_resize(&vlantap->tap))
 198                         return NOTIFY_BAD;
 199                 break;
 200         }
 201
 202         return NOTIFY_DONE;
 203 }
 204
 205 static struct notifier_block macvtap_notifier_block __read_mostly = {
 206         .notifier_call  = macvtap_device_event,
 207 };
 208
 209 static int __init macvtap_init(void)
 210 {
 211         int err;
 212
 213         err = tap_create_cdev(&macvtap_cdev, &macvtap_major, "macvtap",
 214                               THIS_MODULE);
 215         if (err)
 216                 goto out1;
 217
 218         err = class_register(&macvtap_class);
 219         if (err)
 220                 goto out2;
 221
 222         err = register_netdevice_notifier(&macvtap_notifier_block);
 223         if (err)
 224                 goto out3;
 225
 226         err = macvlan_link_register(&macvtap_link_ops);
 227         if (err)
 228                 goto out4;
 229
 230         return 0;
 231
 232 out4:
 233         unregister_netdevice_notifier(&macvtap_notifier_block);
 234 out3:
 235         class_unregister(&macvtap_class);
 236 out2:
 237         tap_destroy_cdev(macvtap_major, &macvtap_cdev);
 238 out1:
 239         return err;
 240 }
 241 module_init(macvtap_init);
 242
 243 static void __exit macvtap_exit(void)
 244 {
 245         rtnl_link_unregister(&macvtap_link_ops);
 246         unregister_netdevice_notifier(&macvtap_notifier_block);
 247         class_unregister(&macvtap_class);
 248         tap_destroy_cdev(macvtap_major, &macvtap_cdev);
 249 }
 250 module_exit(macvtap_exit);
 251
 252 MODULE_ALIAS_RTNL_LINK("macvtap");
 253 MODULE_DESCRIPTION("MAC-VLAN based tap driver");
 254 MODULE_AUTHOR("Arnd Bergmann <arnd@arndb.de>");
 255 MODULE_LICENSE("GPL");