drivers/net/macvtap.c

0001 // SPDX-License-Identifier: GPL-2.0-only
0002 #include <linux/etherdevice.h>
0003 #include <linux/if_macvlan.h>
0004 #include <linux/if_tap.h>
0005 #include <linux/if_vlan.h>
0006 #include <linux/interrupt.h>
0007 #include <linux/nsproxy.h>
0008 #include <linux/compat.h>
0009 #include <linux/if_tun.h>
0010 #include <linux/module.h>
0011 #include <linux/skbuff.h>
0012 #include <linux/cache.h>
0013 #include <linux/sched/signal.h>
0014 #include <linux/types.h>
0015 #include <linux/slab.h>
0016 #include <linux/wait.h>
0017 #include <linux/cdev.h>
0018 #include <linux/idr.h>
0019 #include <linux/fs.h>
0020 #include <linux/uio.h>
0021
0022 #include <net/net_namespace.h>
0023 #include <net/rtnetlink.h>
0024 #include <net/sock.h>
0025 #include <linux/virtio_net.h>
0026 #include <linux/skb_array.h>
0027
0028 struct macvtap_dev {
0029     struct macvlan_dev vlan;
0030     struct tap_dev    tap;
0031 };
0032
0033 /*
0034  * Variables for dealing with macvtaps device numbers.
0035  */
0036 static dev_t macvtap_major;
0037
0038 static const void *macvtap_net_namespace(struct device *d)
0039 {
0040     struct net_device *dev = to_net_dev(d->parent);
0041     return dev_net(dev);
0042 }
0043
0044 static struct class macvtap_class = {
0045     .name = "macvtap",
0046     .owner = THIS_MODULE,
0047     .ns_type = &net_ns_type_operations,
0048     .namespace = macvtap_net_namespace,
0049 };
0050 static struct cdev macvtap_cdev;
0051
0052 #define TUN_OFFLOADS (NETIF_F_HW_CSUM | NETIF_F_TSO_ECN | NETIF_F_TSO | \
0053               NETIF_F_TSO6)
0054
0055 static void macvtap_count_tx_dropped(struct tap_dev *tap)
0056 {
0057     struct macvtap_dev *vlantap = container_of(tap, struct macvtap_dev, tap);
0058     struct macvlan_dev *vlan = &vlantap->vlan;
0059
0060     this_cpu_inc(vlan->pcpu_stats->tx_dropped);
0061 }
0062
0063 static void macvtap_count_rx_dropped(struct tap_dev *tap)
0064 {
0065     struct macvtap_dev *vlantap = container_of(tap, struct macvtap_dev, tap);
0066     struct macvlan_dev *vlan = &vlantap->vlan;
0067
0068     macvlan_count_rx(vlan, 0, 0, 0);
0069 }
0070
0071 static void macvtap_update_features(struct tap_dev *tap,
0072                     netdev_features_t features)
0073 {
0074     struct macvtap_dev *vlantap = container_of(tap, struct macvtap_dev, tap);
0075     struct macvlan_dev *vlan = &vlantap->vlan;
0076
0077     vlan->set_features = features;
0078     netdev_update_features(vlan->dev);
0079 }
0080
0081 static int macvtap_newlink(struct net *src_net, struct net_device *dev,
0082                struct nlattr *tb[], struct nlattr *data[],
0083                struct netlink_ext_ack *extack)
0084 {
0085     struct macvtap_dev *vlantap = netdev_priv(dev);
0086     int err;
0087
0088     INIT_LIST_HEAD(&vlantap->tap.queue_list);
0089
0090     /* Since macvlan supports all offloads by default, make
0091      * tap support all offloads also.
0092      */
0093     vlantap->tap.tap_features = TUN_OFFLOADS;
0094
0095     /* Register callbacks for rx/tx drops accounting and updating
0096      * net_device features
0097      */
0098     vlantap->tap.count_tx_dropped = macvtap_count_tx_dropped;
0099     vlantap->tap.count_rx_dropped = macvtap_count_rx_dropped;
0100     vlantap->tap.update_features  = macvtap_update_features;
0101
0102     err = netdev_rx_handler_register(dev, tap_handle_frame, &vlantap->tap);
0103     if (err)
0104         return err;
0105
0106     /* Don't put anything that may fail after macvlan_common_newlink
0107      * because we can't undo what it does.
0108      */
0109     err = macvlan_common_newlink(src_net, dev, tb, data, extack);
0110     if (err) {
0111         netdev_rx_handler_unregister(dev);
0112         return err;
0113     }
0114
0115     vlantap->tap.dev = vlantap->vlan.dev;
0116
0117     return 0;
0118 }
0119
0120 static void macvtap_dellink(struct net_device *dev,
0121                 struct list_head *head)
0122 {
0123     struct macvtap_dev *vlantap = netdev_priv(dev);
0124
0125     netdev_rx_handler_unregister(dev);
0126     tap_del_queues(&vlantap->tap);
0127     macvlan_dellink(dev, head);
0128 }
0129
0130 static void macvtap_setup(struct net_device *dev)
0131 {
0132     macvlan_common_setup(dev);
0133     dev->tx_queue_len = TUN_READQ_SIZE;
0134 }
0135
0136 static struct net *macvtap_link_net(const struct net_device *dev)
0137 {
0138     return dev_net(macvlan_dev_real_dev(dev));
0139 }
0140
0141 static struct rtnl_link_ops macvtap_link_ops __read_mostly = {
0142     .kind       = "macvtap",
0143     .setup      = macvtap_setup,
0144     .newlink    = macvtap_newlink,
0145     .dellink    = macvtap_dellink,
0146     .get_link_net   = macvtap_link_net,
0147     .priv_size      = sizeof(struct macvtap_dev),
0148 };
0149
0150 static int macvtap_device_event(struct notifier_block *unused,
0151                 unsigned long event, void *ptr)
0152 {
0153     struct net_device *dev = netdev_notifier_info_to_dev(ptr);
0154     struct macvtap_dev *vlantap;
0155     struct device *classdev;
0156     dev_t devt;
0157     int err;
0158     char tap_name[IFNAMSIZ];
0159
0160     if (dev->rtnl_link_ops != &macvtap_link_ops)
0161         return NOTIFY_DONE;
0162
0163     snprintf(tap_name, IFNAMSIZ, "tap%d", dev->ifindex);
0164     vlantap = netdev_priv(dev);
0165
0166     switch (event) {
0167     case NETDEV_REGISTER:
0168         /* Create the device node here after the network device has
0169          * been registered but before register_netdevice has
0170          * finished running.
0171          */
0172         err = tap_get_minor(macvtap_major, &vlantap->tap);
0173         if (err)
0174             return notifier_from_errno(err);
0175
0176         devt = MKDEV(MAJOR(macvtap_major), vlantap->tap.minor);
0177         classdev = device_create(&macvtap_class, &dev->dev, devt,
0178                      dev, "%s", tap_name);
0179         if (IS_ERR(classdev)) {
0180             tap_free_minor(macvtap_major, &vlantap->tap);
0181             return notifier_from_errno(PTR_ERR(classdev));
0182         }
0183         err = sysfs_create_link(&dev->dev.kobj, &classdev->kobj,
0184                     tap_name);
0185         if (err)
0186             return notifier_from_errno(err);
0187         break;
0188     case NETDEV_UNREGISTER:
0189         /* vlan->minor == 0 if NETDEV_REGISTER above failed */
0190         if (vlantap->tap.minor == 0)
0191             break;
0192         sysfs_remove_link(&dev->dev.kobj, tap_name);
0193         devt = MKDEV(MAJOR(macvtap_major), vlantap->tap.minor);
0194         device_destroy(&macvtap_class, devt);
0195         tap_free_minor(macvtap_major, &vlantap->tap);
0196         break;
0197     case NETDEV_CHANGE_TX_QUEUE_LEN:
0198         if (tap_queue_resize(&vlantap->tap))
0199             return NOTIFY_BAD;
0200         break;
0201     }
0202
0203     return NOTIFY_DONE;
0204 }
0205
0206 static struct notifier_block macvtap_notifier_block __read_mostly = {
0207     .notifier_call  = macvtap_device_event,
0208 };
0209
0210 static int macvtap_init(void)
0211 {
0212     int err;
0213
0214     err = tap_create_cdev(&macvtap_cdev, &macvtap_major, "macvtap",
0215                   THIS_MODULE);
0216     if (err)
0217         goto out1;
0218
0219     err = class_register(&macvtap_class);
0220     if (err)
0221         goto out2;
0222
0223     err = register_netdevice_notifier(&macvtap_notifier_block);
0224     if (err)
0225         goto out3;
0226
0227     err = macvlan_link_register(&macvtap_link_ops);
0228     if (err)
0229         goto out4;
0230
0231     return 0;
0232
0233 out4:
0234     unregister_netdevice_notifier(&macvtap_notifier_block);
0235 out3:
0236     class_unregister(&macvtap_class);
0237 out2:
0238     tap_destroy_cdev(macvtap_major, &macvtap_cdev);
0239 out1:
0240     return err;
0241 }
0242 module_init(macvtap_init);
0243
0244 static void macvtap_exit(void)
0245 {
0246     rtnl_link_unregister(&macvtap_link_ops);
0247     unregister_netdevice_notifier(&macvtap_notifier_block);
0248     class_unregister(&macvtap_class);
0249     tap_destroy_cdev(macvtap_major, &macvtap_cdev);
0250 }
0251 module_exit(macvtap_exit);
0252
0253 MODULE_ALIAS_RTNL_LINK("macvtap");
0254 MODULE_AUTHOR("Arnd Bergmann <arnd@arndb.de>");
0255 MODULE_LICENSE("GPL");