l2tp: fix a lockdep splat
[linux-3.10.git] / net / l2tp / l2tp_eth.c
1 /*
2  * L2TPv3 ethernet pseudowire driver
3  *
4  * Copyright (c) 2008,2009,2010 Katalix Systems Ltd
5  *
6  *      This program is free software; you can redistribute it and/or
7  *      modify it under the terms of the GNU General Public License
8  *      as published by the Free Software Foundation; either version
9  *      2 of the License, or (at your option) any later version.
10  */
11
12 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
13
14 #include <linux/module.h>
15 #include <linux/skbuff.h>
16 #include <linux/socket.h>
17 #include <linux/hash.h>
18 #include <linux/l2tp.h>
19 #include <linux/in.h>
20 #include <linux/etherdevice.h>
21 #include <linux/spinlock.h>
22 #include <net/sock.h>
23 #include <net/ip.h>
24 #include <net/icmp.h>
25 #include <net/udp.h>
26 #include <net/inet_common.h>
27 #include <net/inet_hashtables.h>
28 #include <net/tcp_states.h>
29 #include <net/protocol.h>
30 #include <net/xfrm.h>
31 #include <net/net_namespace.h>
32 #include <net/netns/generic.h>
33
34 #include "l2tp_core.h"
35
36 /* Default device name. May be overridden by name specified by user */
37 #define L2TP_ETH_DEV_NAME       "l2tpeth%d"
38
39 /* via netdev_priv() */
40 struct l2tp_eth {
41         struct net_device       *dev;
42         struct sock             *tunnel_sock;
43         struct l2tp_session     *session;
44         struct list_head        list;
45         atomic_long_t           tx_bytes;
46         atomic_long_t           tx_packets;
47         atomic_long_t           tx_dropped;
48         atomic_long_t           rx_bytes;
49         atomic_long_t           rx_packets;
50         atomic_long_t           rx_errors;
51 };
52
53 /* via l2tp_session_priv() */
54 struct l2tp_eth_sess {
55         struct net_device       *dev;
56 };
57
58 /* per-net private data for this module */
59 static unsigned int l2tp_eth_net_id;
60 struct l2tp_eth_net {
61         struct list_head l2tp_eth_dev_list;
62         spinlock_t l2tp_eth_lock;
63 };
64
65 static inline struct l2tp_eth_net *l2tp_eth_pernet(struct net *net)
66 {
67         return net_generic(net, l2tp_eth_net_id);
68 }
69
70 static int l2tp_eth_dev_init(struct net_device *dev)
71 {
72         struct l2tp_eth *priv = netdev_priv(dev);
73
74         priv->dev = dev;
75         eth_hw_addr_random(dev);
76         memset(&dev->broadcast[0], 0xff, 6);
77
78         return 0;
79 }
80
81 static void l2tp_eth_dev_uninit(struct net_device *dev)
82 {
83         struct l2tp_eth *priv = netdev_priv(dev);
84         struct l2tp_eth_net *pn = l2tp_eth_pernet(dev_net(dev));
85
86         spin_lock(&pn->l2tp_eth_lock);
87         list_del_init(&priv->list);
88         spin_unlock(&pn->l2tp_eth_lock);
89         dev_put(dev);
90 }
91
92 static int l2tp_eth_dev_xmit(struct sk_buff *skb, struct net_device *dev)
93 {
94         struct l2tp_eth *priv = netdev_priv(dev);
95         struct l2tp_session *session = priv->session;
96         unsigned int len = skb->len;
97         int ret = l2tp_xmit_skb(session, skb, session->hdr_len);
98
99         if (likely(ret == NET_XMIT_SUCCESS)) {
100                 atomic_long_add(len, &priv->tx_bytes);
101                 atomic_long_inc(&priv->tx_packets);
102         } else {
103                 atomic_long_inc(&priv->tx_dropped);
104         }
105         return NETDEV_TX_OK;
106 }
107
108 static struct rtnl_link_stats64 *l2tp_eth_get_stats64(struct net_device *dev,
109                                                       struct rtnl_link_stats64 *stats)
110 {
111         struct l2tp_eth *priv = netdev_priv(dev);
112
113         stats->tx_bytes   = atomic_long_read(&priv->tx_bytes);
114         stats->tx_packets = atomic_long_read(&priv->tx_packets);
115         stats->tx_dropped = atomic_long_read(&priv->tx_dropped);
116         stats->rx_bytes   = atomic_long_read(&priv->rx_bytes);
117         stats->rx_packets = atomic_long_read(&priv->rx_packets);
118         stats->rx_errors  = atomic_long_read(&priv->rx_errors);
119         return stats;
120 }
121
122
123 static struct net_device_ops l2tp_eth_netdev_ops = {
124         .ndo_init               = l2tp_eth_dev_init,
125         .ndo_uninit             = l2tp_eth_dev_uninit,
126         .ndo_start_xmit         = l2tp_eth_dev_xmit,
127         .ndo_get_stats64        = l2tp_eth_get_stats64,
128 };
129
130 static void l2tp_eth_dev_setup(struct net_device *dev)
131 {
132         ether_setup(dev);
133         dev->priv_flags         &= ~IFF_TX_SKB_SHARING;
134         dev->features           |= NETIF_F_LLTX;
135         dev->netdev_ops         = &l2tp_eth_netdev_ops;
136         dev->destructor         = free_netdev;
137 }
138
139 static void l2tp_eth_dev_recv(struct l2tp_session *session, struct sk_buff *skb, int data_len)
140 {
141         struct l2tp_eth_sess *spriv = l2tp_session_priv(session);
142         struct net_device *dev = spriv->dev;
143         struct l2tp_eth *priv = netdev_priv(dev);
144
145         if (session->debug & L2TP_MSG_DATA) {
146                 unsigned int length;
147
148                 length = min(32u, skb->len);
149                 if (!pskb_may_pull(skb, length))
150                         goto error;
151
152                 pr_debug("%s: eth recv\n", session->name);
153                 print_hex_dump_bytes("", DUMP_PREFIX_OFFSET, skb->data, length);
154         }
155
156         if (!pskb_may_pull(skb, sizeof(ETH_HLEN)))
157                 goto error;
158
159         secpath_reset(skb);
160
161         /* checksums verified by L2TP */
162         skb->ip_summed = CHECKSUM_NONE;
163
164         skb_dst_drop(skb);
165         nf_reset(skb);
166
167         if (dev_forward_skb(dev, skb) == NET_RX_SUCCESS) {
168                 atomic_long_inc(&priv->rx_packets);
169                 atomic_long_add(data_len, &priv->rx_bytes);
170         } else {
171                 atomic_long_inc(&priv->rx_errors);
172         }
173         return;
174
175 error:
176         atomic_long_inc(&priv->rx_errors);
177         kfree_skb(skb);
178 }
179
180 static void l2tp_eth_delete(struct l2tp_session *session)
181 {
182         struct l2tp_eth_sess *spriv;
183         struct net_device *dev;
184
185         if (session) {
186                 spriv = l2tp_session_priv(session);
187                 dev = spriv->dev;
188                 if (dev) {
189                         unregister_netdev(dev);
190                         spriv->dev = NULL;
191                         module_put(THIS_MODULE);
192                 }
193         }
194 }
195
196 #if defined(CONFIG_L2TP_DEBUGFS) || defined(CONFIG_L2TP_DEBUGFS_MODULE)
197 static void l2tp_eth_show(struct seq_file *m, void *arg)
198 {
199         struct l2tp_session *session = arg;
200         struct l2tp_eth_sess *spriv = l2tp_session_priv(session);
201         struct net_device *dev = spriv->dev;
202
203         seq_printf(m, "   interface %s\n", dev->name);
204 }
205 #endif
206
207 static int l2tp_eth_create(struct net *net, u32 tunnel_id, u32 session_id, u32 peer_session_id, struct l2tp_session_cfg *cfg)
208 {
209         struct net_device *dev;
210         char name[IFNAMSIZ];
211         struct l2tp_tunnel *tunnel;
212         struct l2tp_session *session;
213         struct l2tp_eth *priv;
214         struct l2tp_eth_sess *spriv;
215         int rc;
216         struct l2tp_eth_net *pn;
217
218         tunnel = l2tp_tunnel_find(net, tunnel_id);
219         if (!tunnel) {
220                 rc = -ENODEV;
221                 goto out;
222         }
223
224         session = l2tp_session_find(net, tunnel, session_id);
225         if (session) {
226                 rc = -EEXIST;
227                 goto out;
228         }
229
230         if (cfg->ifname) {
231                 dev = dev_get_by_name(net, cfg->ifname);
232                 if (dev) {
233                         dev_put(dev);
234                         rc = -EEXIST;
235                         goto out;
236                 }
237                 strlcpy(name, cfg->ifname, IFNAMSIZ);
238         } else
239                 strcpy(name, L2TP_ETH_DEV_NAME);
240
241         session = l2tp_session_create(sizeof(*spriv), tunnel, session_id,
242                                       peer_session_id, cfg);
243         if (!session) {
244                 rc = -ENOMEM;
245                 goto out;
246         }
247
248         dev = alloc_netdev(sizeof(*priv), name, l2tp_eth_dev_setup);
249         if (!dev) {
250                 rc = -ENOMEM;
251                 goto out_del_session;
252         }
253
254         dev_net_set(dev, net);
255         if (session->mtu == 0)
256                 session->mtu = dev->mtu - session->hdr_len;
257         dev->mtu = session->mtu;
258         dev->needed_headroom += session->hdr_len;
259
260         priv = netdev_priv(dev);
261         priv->dev = dev;
262         priv->session = session;
263         INIT_LIST_HEAD(&priv->list);
264
265         priv->tunnel_sock = tunnel->sock;
266         session->recv_skb = l2tp_eth_dev_recv;
267         session->session_close = l2tp_eth_delete;
268 #if defined(CONFIG_L2TP_DEBUGFS) || defined(CONFIG_L2TP_DEBUGFS_MODULE)
269         session->show = l2tp_eth_show;
270 #endif
271
272         spriv = l2tp_session_priv(session);
273         spriv->dev = dev;
274
275         rc = register_netdev(dev);
276         if (rc < 0)
277                 goto out_del_dev;
278
279         __module_get(THIS_MODULE);
280         /* Must be done after register_netdev() */
281         strlcpy(session->ifname, dev->name, IFNAMSIZ);
282
283         dev_hold(dev);
284         pn = l2tp_eth_pernet(dev_net(dev));
285         spin_lock(&pn->l2tp_eth_lock);
286         list_add(&priv->list, &pn->l2tp_eth_dev_list);
287         spin_unlock(&pn->l2tp_eth_lock);
288
289         return 0;
290
291 out_del_dev:
292         free_netdev(dev);
293 out_del_session:
294         l2tp_session_delete(session);
295 out:
296         return rc;
297 }
298
299 static __net_init int l2tp_eth_init_net(struct net *net)
300 {
301         struct l2tp_eth_net *pn = net_generic(net, l2tp_eth_net_id);
302
303         INIT_LIST_HEAD(&pn->l2tp_eth_dev_list);
304         spin_lock_init(&pn->l2tp_eth_lock);
305
306         return 0;
307 }
308
309 static struct pernet_operations l2tp_eth_net_ops = {
310         .init = l2tp_eth_init_net,
311         .id   = &l2tp_eth_net_id,
312         .size = sizeof(struct l2tp_eth_net),
313 };
314
315
316 static const struct l2tp_nl_cmd_ops l2tp_eth_nl_cmd_ops = {
317         .session_create = l2tp_eth_create,
318         .session_delete = l2tp_session_delete,
319 };
320
321
322 static int __init l2tp_eth_init(void)
323 {
324         int err = 0;
325
326         err = l2tp_nl_register_ops(L2TP_PWTYPE_ETH, &l2tp_eth_nl_cmd_ops);
327         if (err)
328                 goto out;
329
330         err = register_pernet_device(&l2tp_eth_net_ops);
331         if (err)
332                 goto out_unreg;
333
334         pr_info("L2TP ethernet pseudowire support (L2TPv3)\n");
335
336         return 0;
337
338 out_unreg:
339         l2tp_nl_unregister_ops(L2TP_PWTYPE_ETH);
340 out:
341         return err;
342 }
343
344 static void __exit l2tp_eth_exit(void)
345 {
346         unregister_pernet_device(&l2tp_eth_net_ops);
347         l2tp_nl_unregister_ops(L2TP_PWTYPE_ETH);
348 }
349
350 module_init(l2tp_eth_init);
351 module_exit(l2tp_eth_exit);
352
353 MODULE_LICENSE("GPL");
354 MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
355 MODULE_DESCRIPTION("L2TP ethernet pseudowire driver");
356 MODULE_VERSION("1.0");