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() */
40struct 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() */
54struct l2tp_eth_sess {
55	struct net_device	*dev;
56};
57
58/* per-net private data for this module */
59static unsigned int l2tp_eth_net_id;
60struct l2tp_eth_net {
61	struct list_head l2tp_eth_dev_list;
62	spinlock_t l2tp_eth_lock;
63};
64
65static inline struct l2tp_eth_net *l2tp_eth_pernet(struct net *net)
66{
67	return net_generic(net, l2tp_eth_net_id);
68}
69
70static struct lock_class_key l2tp_eth_tx_busylock;
71static int l2tp_eth_dev_init(struct net_device *dev)
72{
73	struct l2tp_eth *priv = netdev_priv(dev);
74
75	priv->dev = dev;
76	eth_hw_addr_random(dev);
77	eth_broadcast_addr(dev->broadcast);
78	dev->qdisc_tx_busylock = &l2tp_eth_tx_busylock;
79	return 0;
80}
81
82static void l2tp_eth_dev_uninit(struct net_device *dev)
83{
84	struct l2tp_eth *priv = netdev_priv(dev);
85	struct l2tp_eth_net *pn = l2tp_eth_pernet(dev_net(dev));
86
87	spin_lock(&pn->l2tp_eth_lock);
88	list_del_init(&priv->list);
89	spin_unlock(&pn->l2tp_eth_lock);
90	dev_put(dev);
91}
92
93static int l2tp_eth_dev_xmit(struct sk_buff *skb, struct net_device *dev)
94{
95	struct l2tp_eth *priv = netdev_priv(dev);
96	struct l2tp_session *session = priv->session;
97	unsigned int len = skb->len;
98	int ret = l2tp_xmit_skb(session, skb, session->hdr_len);
99
100	if (likely(ret == NET_XMIT_SUCCESS)) {
101		atomic_long_add(len, &priv->tx_bytes);
102		atomic_long_inc(&priv->tx_packets);
103	} else {
104		atomic_long_inc(&priv->tx_dropped);
105	}
106	return NETDEV_TX_OK;
107}
108
109static struct rtnl_link_stats64 *l2tp_eth_get_stats64(struct net_device *dev,
110						      struct rtnl_link_stats64 *stats)
111{
112	struct l2tp_eth *priv = netdev_priv(dev);
113
114	stats->tx_bytes   = atomic_long_read(&priv->tx_bytes);
115	stats->tx_packets = atomic_long_read(&priv->tx_packets);
116	stats->tx_dropped = atomic_long_read(&priv->tx_dropped);
117	stats->rx_bytes   = atomic_long_read(&priv->rx_bytes);
118	stats->rx_packets = atomic_long_read(&priv->rx_packets);
119	stats->rx_errors  = atomic_long_read(&priv->rx_errors);
120	return stats;
121}
122
123
124static struct net_device_ops l2tp_eth_netdev_ops = {
125	.ndo_init		= l2tp_eth_dev_init,
126	.ndo_uninit		= l2tp_eth_dev_uninit,
127	.ndo_start_xmit		= l2tp_eth_dev_xmit,
128	.ndo_get_stats64	= l2tp_eth_get_stats64,
129	.ndo_set_mac_address	= eth_mac_addr,
130};
131
132static void l2tp_eth_dev_setup(struct net_device *dev)
133{
134	ether_setup(dev);
135	dev->priv_flags		&= ~IFF_TX_SKB_SHARING;
136	dev->features		|= NETIF_F_LLTX;
137	dev->netdev_ops		= &l2tp_eth_netdev_ops;
138	dev->destructor		= free_netdev;
139}
140
141static void l2tp_eth_dev_recv(struct l2tp_session *session, struct sk_buff *skb, int data_len)
142{
143	struct l2tp_eth_sess *spriv = l2tp_session_priv(session);
144	struct net_device *dev = spriv->dev;
145	struct l2tp_eth *priv = netdev_priv(dev);
146
147	if (session->debug & L2TP_MSG_DATA) {
148		unsigned int length;
149
150		length = min(32u, skb->len);
151		if (!pskb_may_pull(skb, length))
152			goto error;
153
154		pr_debug("%s: eth recv\n", session->name);
155		print_hex_dump_bytes("", DUMP_PREFIX_OFFSET, skb->data, length);
156	}
157
158	if (!pskb_may_pull(skb, ETH_HLEN))
159		goto error;
160
161	secpath_reset(skb);
162
163	/* checksums verified by L2TP */
164	skb->ip_summed = CHECKSUM_NONE;
165
166	skb_dst_drop(skb);
167	nf_reset(skb);
168
169	if (dev_forward_skb(dev, skb) == NET_RX_SUCCESS) {
170		atomic_long_inc(&priv->rx_packets);
171		atomic_long_add(data_len, &priv->rx_bytes);
172	} else {
173		atomic_long_inc(&priv->rx_errors);
174	}
175	return;
176
177error:
178	atomic_long_inc(&priv->rx_errors);
179	kfree_skb(skb);
180}
181
182static void l2tp_eth_delete(struct l2tp_session *session)
183{
184	struct l2tp_eth_sess *spriv;
185	struct net_device *dev;
186
187	if (session) {
188		spriv = l2tp_session_priv(session);
189		dev = spriv->dev;
190		if (dev) {
191			unregister_netdev(dev);
192			spriv->dev = NULL;
193			module_put(THIS_MODULE);
194		}
195	}
196}
197
198#if defined(CONFIG_L2TP_DEBUGFS) || defined(CONFIG_L2TP_DEBUGFS_MODULE)
199static void l2tp_eth_show(struct seq_file *m, void *arg)
200{
201	struct l2tp_session *session = arg;
202	struct l2tp_eth_sess *spriv = l2tp_session_priv(session);
203	struct net_device *dev = spriv->dev;
204
205	seq_printf(m, "   interface %s\n", dev->name);
206}
207#endif
208
209static int l2tp_eth_create(struct net *net, u32 tunnel_id, u32 session_id, u32 peer_session_id, struct l2tp_session_cfg *cfg)
210{
211	struct net_device *dev;
212	char name[IFNAMSIZ];
213	struct l2tp_tunnel *tunnel;
214	struct l2tp_session *session;
215	struct l2tp_eth *priv;
216	struct l2tp_eth_sess *spriv;
217	int rc;
218	struct l2tp_eth_net *pn;
219
220	tunnel = l2tp_tunnel_find(net, tunnel_id);
221	if (!tunnel) {
222		rc = -ENODEV;
223		goto out;
224	}
225
226	session = l2tp_session_find(net, tunnel, session_id);
227	if (session) {
228		rc = -EEXIST;
229		goto out;
230	}
231
232	if (cfg->ifname) {
233		dev = dev_get_by_name(net, cfg->ifname);
234		if (dev) {
235			dev_put(dev);
236			rc = -EEXIST;
237			goto out;
238		}
239		strlcpy(name, cfg->ifname, IFNAMSIZ);
240	} else
241		strcpy(name, L2TP_ETH_DEV_NAME);
242
243	session = l2tp_session_create(sizeof(*spriv), tunnel, session_id,
244				      peer_session_id, cfg);
245	if (!session) {
246		rc = -ENOMEM;
247		goto out;
248	}
249
250	dev = alloc_netdev(sizeof(*priv), name, NET_NAME_UNKNOWN,
251			   l2tp_eth_dev_setup);
252	if (!dev) {
253		rc = -ENOMEM;
254		goto out_del_session;
255	}
256
257	dev_net_set(dev, net);
258	if (session->mtu == 0)
259		session->mtu = dev->mtu - session->hdr_len;
260	dev->mtu = session->mtu;
261	dev->needed_headroom += session->hdr_len;
262
263	priv = netdev_priv(dev);
264	priv->dev = dev;
265	priv->session = session;
266	INIT_LIST_HEAD(&priv->list);
267
268	priv->tunnel_sock = tunnel->sock;
269	session->recv_skb = l2tp_eth_dev_recv;
270	session->session_close = l2tp_eth_delete;
271#if defined(CONFIG_L2TP_DEBUGFS) || defined(CONFIG_L2TP_DEBUGFS_MODULE)
272	session->show = l2tp_eth_show;
273#endif
274
275	spriv = l2tp_session_priv(session);
276	spriv->dev = dev;
277
278	rc = register_netdev(dev);
279	if (rc < 0)
280		goto out_del_dev;
281
282	__module_get(THIS_MODULE);
283	/* Must be done after register_netdev() */
284	strlcpy(session->ifname, dev->name, IFNAMSIZ);
285
286	dev_hold(dev);
287	pn = l2tp_eth_pernet(dev_net(dev));
288	spin_lock(&pn->l2tp_eth_lock);
289	list_add(&priv->list, &pn->l2tp_eth_dev_list);
290	spin_unlock(&pn->l2tp_eth_lock);
291
292	return 0;
293
294out_del_dev:
295	free_netdev(dev);
296	spriv->dev = NULL;
297out_del_session:
298	l2tp_session_delete(session);
299out:
300	return rc;
301}
302
303static __net_init int l2tp_eth_init_net(struct net *net)
304{
305	struct l2tp_eth_net *pn = net_generic(net, l2tp_eth_net_id);
306
307	INIT_LIST_HEAD(&pn->l2tp_eth_dev_list);
308	spin_lock_init(&pn->l2tp_eth_lock);
309
310	return 0;
311}
312
313static struct pernet_operations l2tp_eth_net_ops = {
314	.init = l2tp_eth_init_net,
315	.id   = &l2tp_eth_net_id,
316	.size = sizeof(struct l2tp_eth_net),
317};
318
319
320static const struct l2tp_nl_cmd_ops l2tp_eth_nl_cmd_ops = {
321	.session_create	= l2tp_eth_create,
322	.session_delete	= l2tp_session_delete,
323};
324
325
326static int __init l2tp_eth_init(void)
327{
328	int err = 0;
329
330	err = l2tp_nl_register_ops(L2TP_PWTYPE_ETH, &l2tp_eth_nl_cmd_ops);
331	if (err)
332		goto out;
333
334	err = register_pernet_device(&l2tp_eth_net_ops);
335	if (err)
336		goto out_unreg;
337
338	pr_info("L2TP ethernet pseudowire support (L2TPv3)\n");
339
340	return 0;
341
342out_unreg:
343	l2tp_nl_unregister_ops(L2TP_PWTYPE_ETH);
344out:
345	return err;
346}
347
348static void __exit l2tp_eth_exit(void)
349{
350	unregister_pernet_device(&l2tp_eth_net_ops);
351	l2tp_nl_unregister_ops(L2TP_PWTYPE_ETH);
352}
353
354module_init(l2tp_eth_init);
355module_exit(l2tp_eth_exit);
356
357MODULE_LICENSE("GPL");
358MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
359MODULE_DESCRIPTION("L2TP ethernet pseudowire driver");
360MODULE_VERSION("1.0");
361MODULE_ALIAS_L2TP_PWTYPE(5);
362