tap: reference to KVA of an unloaded module causes kernel panic
[sfrench/cifs-2.6.git] / drivers / net / ipvlan / ipvtap.c
1 #include <linux/etherdevice.h>
2 #include "ipvlan.h"
3 #include <linux/if_vlan.h>
4 #include <linux/if_tap.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.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
26 #define TUN_OFFLOADS (NETIF_F_HW_CSUM | NETIF_F_TSO_ECN | NETIF_F_TSO | \
27                       NETIF_F_TSO6)
28
29 static dev_t ipvtap_major;
30 static struct cdev ipvtap_cdev;
31
32 static const void *ipvtap_net_namespace(struct device *d)
33 {
34         struct net_device *dev = to_net_dev(d->parent);
35         return dev_net(dev);
36 }
37
38 static struct class ipvtap_class = {
39          .name = "ipvtap",
40          .owner = THIS_MODULE,
41          .ns_type = &net_ns_type_operations,
42          .namespace = ipvtap_net_namespace,
43 };
44
45 struct ipvtap_dev {
46         struct ipvl_dev vlan;
47         struct tap_dev    tap;
48 };
49
50 static void ipvtap_count_tx_dropped(struct tap_dev *tap)
51 {
52         struct ipvtap_dev *vlantap = container_of(tap, struct ipvtap_dev, tap);
53         struct ipvl_dev *vlan = &vlantap->vlan;
54
55         this_cpu_inc(vlan->pcpu_stats->tx_drps);
56 }
57
58 static void ipvtap_count_rx_dropped(struct tap_dev *tap)
59 {
60         struct ipvtap_dev *vlantap = container_of(tap, struct ipvtap_dev, tap);
61         struct ipvl_dev *vlan = &vlantap->vlan;
62
63         ipvlan_count_rx(vlan, 0, 0, 0);
64 }
65
66 static void ipvtap_update_features(struct tap_dev *tap,
67                                    netdev_features_t features)
68 {
69         struct ipvtap_dev *vlantap = container_of(tap, struct ipvtap_dev, tap);
70         struct ipvl_dev *vlan = &vlantap->vlan;
71
72         vlan->sfeatures = features;
73         netdev_update_features(vlan->dev);
74 }
75
76 static int ipvtap_newlink(struct net *src_net, struct net_device *dev,
77                           struct nlattr *tb[], struct nlattr *data[],
78                           struct netlink_ext_ack *extack)
79 {
80         struct ipvtap_dev *vlantap = netdev_priv(dev);
81         int err;
82
83         INIT_LIST_HEAD(&vlantap->tap.queue_list);
84
85         /* Since macvlan supports all offloads by default, make
86          * tap support all offloads also.
87          */
88         vlantap->tap.tap_features = TUN_OFFLOADS;
89         vlantap->tap.count_tx_dropped = ipvtap_count_tx_dropped;
90         vlantap->tap.update_features =  ipvtap_update_features;
91         vlantap->tap.count_rx_dropped = ipvtap_count_rx_dropped;
92
93         err = netdev_rx_handler_register(dev, tap_handle_frame, &vlantap->tap);
94         if (err)
95                 return err;
96
97         /* Don't put anything that may fail after macvlan_common_newlink
98          * because we can't undo what it does.
99          */
100         err =  ipvlan_link_new(src_net, dev, tb, data, extack);
101         if (err) {
102                 netdev_rx_handler_unregister(dev);
103                 return err;
104         }
105
106         vlantap->tap.dev = vlantap->vlan.dev;
107
108         return err;
109 }
110
111 static void ipvtap_dellink(struct net_device *dev,
112                            struct list_head *head)
113 {
114         struct ipvtap_dev *vlan = netdev_priv(dev);
115
116         netdev_rx_handler_unregister(dev);
117         tap_del_queues(&vlan->tap);
118         ipvlan_link_delete(dev, head);
119 }
120
121 static void ipvtap_setup(struct net_device *dev)
122 {
123         ipvlan_link_setup(dev);
124         dev->tx_queue_len = TUN_READQ_SIZE;
125         dev->priv_flags &= ~IFF_NO_QUEUE;
126 }
127
128 static struct rtnl_link_ops ipvtap_link_ops __read_mostly = {
129         .kind           = "ipvtap",
130         .setup          = ipvtap_setup,
131         .newlink        = ipvtap_newlink,
132         .dellink        = ipvtap_dellink,
133         .priv_size      = sizeof(struct ipvtap_dev),
134 };
135
136 static int ipvtap_device_event(struct notifier_block *unused,
137                                unsigned long event, void *ptr)
138 {
139         struct net_device *dev = netdev_notifier_info_to_dev(ptr);
140         struct ipvtap_dev *vlantap;
141         struct device *classdev;
142         dev_t devt;
143         int err;
144         char tap_name[IFNAMSIZ];
145
146         if (dev->rtnl_link_ops != &ipvtap_link_ops)
147                 return NOTIFY_DONE;
148
149         snprintf(tap_name, IFNAMSIZ, "tap%d", dev->ifindex);
150         vlantap = netdev_priv(dev);
151
152         switch (event) {
153         case NETDEV_REGISTER:
154                 /* Create the device node here after the network device has
155                  * been registered but before register_netdevice has
156                  * finished running.
157                  */
158                 err = tap_get_minor(ipvtap_major, &vlantap->tap);
159                 if (err)
160                         return notifier_from_errno(err);
161
162                 devt = MKDEV(MAJOR(ipvtap_major), vlantap->tap.minor);
163                 classdev = device_create(&ipvtap_class, &dev->dev, devt,
164                                          dev, tap_name);
165                 if (IS_ERR(classdev)) {
166                         tap_free_minor(ipvtap_major, &vlantap->tap);
167                         return notifier_from_errno(PTR_ERR(classdev));
168                 }
169                 err = sysfs_create_link(&dev->dev.kobj, &classdev->kobj,
170                                         tap_name);
171                 if (err)
172                         return notifier_from_errno(err);
173                 break;
174         case NETDEV_UNREGISTER:
175                 /* vlan->minor == 0 if NETDEV_REGISTER above failed */
176                 if (vlantap->tap.minor == 0)
177                         break;
178                 sysfs_remove_link(&dev->dev.kobj, tap_name);
179                 devt = MKDEV(MAJOR(ipvtap_major), vlantap->tap.minor);
180                 device_destroy(&ipvtap_class, devt);
181                 tap_free_minor(ipvtap_major, &vlantap->tap);
182                 break;
183         case NETDEV_CHANGE_TX_QUEUE_LEN:
184                 if (tap_queue_resize(&vlantap->tap))
185                         return NOTIFY_BAD;
186                 break;
187         }
188
189         return NOTIFY_DONE;
190 }
191
192 static struct notifier_block ipvtap_notifier_block __read_mostly = {
193         .notifier_call  = ipvtap_device_event,
194 };
195
196 static int ipvtap_init(void)
197 {
198         int err;
199
200         err = tap_create_cdev(&ipvtap_cdev, &ipvtap_major, "ipvtap",
201                               THIS_MODULE);
202         if (err)
203                 goto out1;
204
205         err = class_register(&ipvtap_class);
206         if (err)
207                 goto out2;
208
209         err = register_netdevice_notifier(&ipvtap_notifier_block);
210         if (err)
211                 goto out3;
212
213         err = ipvlan_link_register(&ipvtap_link_ops);
214         if (err)
215                 goto out4;
216
217         return 0;
218
219 out4:
220         unregister_netdevice_notifier(&ipvtap_notifier_block);
221 out3:
222         class_unregister(&ipvtap_class);
223 out2:
224         tap_destroy_cdev(ipvtap_major, &ipvtap_cdev);
225 out1:
226         return err;
227 }
228 module_init(ipvtap_init);
229
230 static void ipvtap_exit(void)
231 {
232         rtnl_link_unregister(&ipvtap_link_ops);
233         unregister_netdevice_notifier(&ipvtap_notifier_block);
234         class_unregister(&ipvtap_class);
235         tap_destroy_cdev(ipvtap_major, &ipvtap_cdev);
236 }
237 module_exit(ipvtap_exit);
238 MODULE_ALIAS_RTNL_LINK("ipvtap");
239 MODULE_AUTHOR("Sainath Grandhi <sainath.grandhi@intel.com>");
240 MODULE_LICENSE("GPL");