Root/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() */
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    memset(&dev->broadcast[0], 0xff, 6);
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};
130
131static void l2tp_eth_dev_setup(struct net_device *dev)
132{
133    ether_setup(dev);
134    dev->priv_flags &= ~IFF_TX_SKB_SHARING;
135    dev->features |= NETIF_F_LLTX;
136    dev->netdev_ops = &l2tp_eth_netdev_ops;
137    dev->destructor = free_netdev;
138}
139
140static void l2tp_eth_dev_recv(struct l2tp_session *session, struct sk_buff *skb, int data_len)
141{
142    struct l2tp_eth_sess *spriv = l2tp_session_priv(session);
143    struct net_device *dev = spriv->dev;
144    struct l2tp_eth *priv = netdev_priv(dev);
145
146    if (session->debug & L2TP_MSG_DATA) {
147        unsigned int length;
148
149        length = min(32u, skb->len);
150        if (!pskb_may_pull(skb, length))
151            goto error;
152
153        pr_debug("%s: eth recv\n", session->name);
154        print_hex_dump_bytes("", DUMP_PREFIX_OFFSET, skb->data, length);
155    }
156
157    if (!pskb_may_pull(skb, ETH_HLEN))
158        goto error;
159
160    secpath_reset(skb);
161
162    /* checksums verified by L2TP */
163    skb->ip_summed = CHECKSUM_NONE;
164
165    skb_dst_drop(skb);
166    nf_reset(skb);
167
168    if (dev_forward_skb(dev, skb) == NET_RX_SUCCESS) {
169        atomic_long_inc(&priv->rx_packets);
170        atomic_long_add(data_len, &priv->rx_bytes);
171    } else {
172        atomic_long_inc(&priv->rx_errors);
173    }
174    return;
175
176error:
177    atomic_long_inc(&priv->rx_errors);
178    kfree_skb(skb);
179}
180
181static void l2tp_eth_delete(struct l2tp_session *session)
182{
183    struct l2tp_eth_sess *spriv;
184    struct net_device *dev;
185
186    if (session) {
187        spriv = l2tp_session_priv(session);
188        dev = spriv->dev;
189        if (dev) {
190            unregister_netdev(dev);
191            spriv->dev = NULL;
192            module_put(THIS_MODULE);
193        }
194    }
195}
196
197#if defined(CONFIG_L2TP_DEBUGFS) || defined(CONFIG_L2TP_DEBUGFS_MODULE)
198static void l2tp_eth_show(struct seq_file *m, void *arg)
199{
200    struct l2tp_session *session = arg;
201    struct l2tp_eth_sess *spriv = l2tp_session_priv(session);
202    struct net_device *dev = spriv->dev;
203
204    seq_printf(m, " interface %s\n", dev->name);
205}
206#endif
207
208static int l2tp_eth_create(struct net *net, u32 tunnel_id, u32 session_id, u32 peer_session_id, struct l2tp_session_cfg *cfg)
209{
210    struct net_device *dev;
211    char name[IFNAMSIZ];
212    struct l2tp_tunnel *tunnel;
213    struct l2tp_session *session;
214    struct l2tp_eth *priv;
215    struct l2tp_eth_sess *spriv;
216    int rc;
217    struct l2tp_eth_net *pn;
218
219    tunnel = l2tp_tunnel_find(net, tunnel_id);
220    if (!tunnel) {
221        rc = -ENODEV;
222        goto out;
223    }
224
225    session = l2tp_session_find(net, tunnel, session_id);
226    if (session) {
227        rc = -EEXIST;
228        goto out;
229    }
230
231    if (cfg->ifname) {
232        dev = dev_get_by_name(net, cfg->ifname);
233        if (dev) {
234            dev_put(dev);
235            rc = -EEXIST;
236            goto out;
237        }
238        strlcpy(name, cfg->ifname, IFNAMSIZ);
239    } else
240        strcpy(name, L2TP_ETH_DEV_NAME);
241
242    session = l2tp_session_create(sizeof(*spriv), tunnel, session_id,
243                      peer_session_id, cfg);
244    if (!session) {
245        rc = -ENOMEM;
246        goto out;
247    }
248
249    dev = alloc_netdev(sizeof(*priv), name, l2tp_eth_dev_setup);
250    if (!dev) {
251        rc = -ENOMEM;
252        goto out_del_session;
253    }
254
255    dev_net_set(dev, net);
256    if (session->mtu == 0)
257        session->mtu = dev->mtu - session->hdr_len;
258    dev->mtu = session->mtu;
259    dev->needed_headroom += session->hdr_len;
260
261    priv = netdev_priv(dev);
262    priv->dev = dev;
263    priv->session = session;
264    INIT_LIST_HEAD(&priv->list);
265
266    priv->tunnel_sock = tunnel->sock;
267    session->recv_skb = l2tp_eth_dev_recv;
268    session->session_close = l2tp_eth_delete;
269#if defined(CONFIG_L2TP_DEBUGFS) || defined(CONFIG_L2TP_DEBUGFS_MODULE)
270    session->show = l2tp_eth_show;
271#endif
272
273    spriv = l2tp_session_priv(session);
274    spriv->dev = dev;
275
276    rc = register_netdev(dev);
277    if (rc < 0)
278        goto out_del_dev;
279
280    __module_get(THIS_MODULE);
281    /* Must be done after register_netdev() */
282    strlcpy(session->ifname, dev->name, IFNAMSIZ);
283
284    dev_hold(dev);
285    pn = l2tp_eth_pernet(dev_net(dev));
286    spin_lock(&pn->l2tp_eth_lock);
287    list_add(&priv->list, &pn->l2tp_eth_dev_list);
288    spin_unlock(&pn->l2tp_eth_lock);
289
290    return 0;
291
292out_del_dev:
293    free_netdev(dev);
294    spriv->dev = NULL;
295out_del_session:
296    l2tp_session_delete(session);
297out:
298    return rc;
299}
300
301static __net_init int l2tp_eth_init_net(struct net *net)
302{
303    struct l2tp_eth_net *pn = net_generic(net, l2tp_eth_net_id);
304
305    INIT_LIST_HEAD(&pn->l2tp_eth_dev_list);
306    spin_lock_init(&pn->l2tp_eth_lock);
307
308    return 0;
309}
310
311static struct pernet_operations l2tp_eth_net_ops = {
312    .init = l2tp_eth_init_net,
313    .id = &l2tp_eth_net_id,
314    .size = sizeof(struct l2tp_eth_net),
315};
316
317
318static const struct l2tp_nl_cmd_ops l2tp_eth_nl_cmd_ops = {
319    .session_create = l2tp_eth_create,
320    .session_delete = l2tp_session_delete,
321};
322
323
324static int __init l2tp_eth_init(void)
325{
326    int err = 0;
327
328    err = l2tp_nl_register_ops(L2TP_PWTYPE_ETH, &l2tp_eth_nl_cmd_ops);
329    if (err)
330        goto out;
331
332    err = register_pernet_device(&l2tp_eth_net_ops);
333    if (err)
334        goto out_unreg;
335
336    pr_info("L2TP ethernet pseudowire support (L2TPv3)\n");
337
338    return 0;
339
340out_unreg:
341    l2tp_nl_unregister_ops(L2TP_PWTYPE_ETH);
342out:
343    return err;
344}
345
346static void __exit l2tp_eth_exit(void)
347{
348    unregister_pernet_device(&l2tp_eth_net_ops);
349    l2tp_nl_unregister_ops(L2TP_PWTYPE_ETH);
350}
351
352module_init(l2tp_eth_init);
353module_exit(l2tp_eth_exit);
354
355MODULE_LICENSE("GPL");
356MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
357MODULE_DESCRIPTION("L2TP ethernet pseudowire driver");
358MODULE_VERSION("1.0");
359

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