2 * L2TPv3 ethernet pseudowire driver
4 * Copyright (c) 2008,2009,2010 Katalix Systems Ltd
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.
12 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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>
20 #include <linux/etherdevice.h>
21 #include <linux/spinlock.h>
26 #include <net/inet_common.h>
27 #include <net/inet_hashtables.h>
28 #include <net/tcp_states.h>
29 #include <net/protocol.h>
31 #include <net/net_namespace.h>
32 #include <net/netns/generic.h>
34 #include <linux/ipv6.h>
35 #include <linux/udp.h>
37 #include "l2tp_core.h"
39 /* Default device name. May be overridden by name specified by user */
40 #define L2TP_ETH_DEV_NAME "l2tpeth%d"
42 /* via netdev_priv() */
44 struct net_device *dev;
45 struct sock *tunnel_sock;
46 struct l2tp_session *session;
47 atomic_long_t tx_bytes;
48 atomic_long_t tx_packets;
49 atomic_long_t tx_dropped;
50 atomic_long_t rx_bytes;
51 atomic_long_t rx_packets;
52 atomic_long_t rx_errors;
55 /* via l2tp_session_priv() */
56 struct l2tp_eth_sess {
57 struct net_device __rcu *dev;
61 static int l2tp_eth_dev_init(struct net_device *dev)
63 struct l2tp_eth *priv = netdev_priv(dev);
66 eth_hw_addr_random(dev);
67 eth_broadcast_addr(dev->broadcast);
68 netdev_lockdep_set_classes(dev);
73 static void l2tp_eth_dev_uninit(struct net_device *dev)
75 struct l2tp_eth *priv = netdev_priv(dev);
76 struct l2tp_eth_sess *spriv;
78 spriv = l2tp_session_priv(priv->session);
79 RCU_INIT_POINTER(spriv->dev, NULL);
80 /* No need for synchronize_net() here. We're called by
81 * unregister_netdev*(), which does the synchronisation for us.
85 static int l2tp_eth_dev_xmit(struct sk_buff *skb, struct net_device *dev)
87 struct l2tp_eth *priv = netdev_priv(dev);
88 struct l2tp_session *session = priv->session;
89 unsigned int len = skb->len;
90 int ret = l2tp_xmit_skb(session, skb, session->hdr_len);
92 if (likely(ret == NET_XMIT_SUCCESS)) {
93 atomic_long_add(len, &priv->tx_bytes);
94 atomic_long_inc(&priv->tx_packets);
96 atomic_long_inc(&priv->tx_dropped);
101 static void l2tp_eth_get_stats64(struct net_device *dev,
102 struct rtnl_link_stats64 *stats)
104 struct l2tp_eth *priv = netdev_priv(dev);
106 stats->tx_bytes = (unsigned long) atomic_long_read(&priv->tx_bytes);
107 stats->tx_packets = (unsigned long) atomic_long_read(&priv->tx_packets);
108 stats->tx_dropped = (unsigned long) atomic_long_read(&priv->tx_dropped);
109 stats->rx_bytes = (unsigned long) atomic_long_read(&priv->rx_bytes);
110 stats->rx_packets = (unsigned long) atomic_long_read(&priv->rx_packets);
111 stats->rx_errors = (unsigned long) atomic_long_read(&priv->rx_errors);
115 static const struct net_device_ops l2tp_eth_netdev_ops = {
116 .ndo_init = l2tp_eth_dev_init,
117 .ndo_uninit = l2tp_eth_dev_uninit,
118 .ndo_start_xmit = l2tp_eth_dev_xmit,
119 .ndo_get_stats64 = l2tp_eth_get_stats64,
120 .ndo_set_mac_address = eth_mac_addr,
123 static struct device_type l2tpeth_type = {
127 static void l2tp_eth_dev_setup(struct net_device *dev)
129 SET_NETDEV_DEVTYPE(dev, &l2tpeth_type);
131 dev->priv_flags &= ~IFF_TX_SKB_SHARING;
132 dev->features |= NETIF_F_LLTX;
133 dev->netdev_ops = &l2tp_eth_netdev_ops;
134 dev->needs_free_netdev = true;
137 static void l2tp_eth_dev_recv(struct l2tp_session *session, struct sk_buff *skb, int data_len)
139 struct l2tp_eth_sess *spriv = l2tp_session_priv(session);
140 struct net_device *dev;
141 struct l2tp_eth *priv;
143 if (session->debug & L2TP_MSG_DATA) {
146 length = min(32u, skb->len);
147 if (!pskb_may_pull(skb, length))
150 pr_debug("%s: eth recv\n", session->name);
151 print_hex_dump_bytes("", DUMP_PREFIX_OFFSET, skb->data, length);
154 if (!pskb_may_pull(skb, ETH_HLEN))
159 /* checksums verified by L2TP */
160 skb->ip_summed = CHECKSUM_NONE;
166 dev = rcu_dereference(spriv->dev);
170 priv = netdev_priv(dev);
171 if (dev_forward_skb(dev, skb) == NET_RX_SUCCESS) {
172 atomic_long_inc(&priv->rx_packets);
173 atomic_long_add(data_len, &priv->rx_bytes);
175 atomic_long_inc(&priv->rx_errors);
187 static void l2tp_eth_delete(struct l2tp_session *session)
189 struct l2tp_eth_sess *spriv;
190 struct net_device *dev;
193 spriv = l2tp_session_priv(session);
196 dev = rtnl_dereference(spriv->dev);
198 unregister_netdevice(dev);
200 module_put(THIS_MODULE);
207 #if IS_ENABLED(CONFIG_L2TP_DEBUGFS)
208 static void l2tp_eth_show(struct seq_file *m, void *arg)
210 struct l2tp_session *session = arg;
211 struct l2tp_eth_sess *spriv = l2tp_session_priv(session);
212 struct net_device *dev;
215 dev = rcu_dereference(spriv->dev);
223 seq_printf(m, " interface %s\n", dev->name);
229 static void l2tp_eth_adjust_mtu(struct l2tp_tunnel *tunnel,
230 struct l2tp_session *session,
231 struct net_device *dev)
233 unsigned int overhead = 0;
234 struct dst_entry *dst;
237 /* if the encap is UDP, account for UDP header size */
238 if (tunnel->encap == L2TP_ENCAPTYPE_UDP) {
239 overhead += sizeof(struct udphdr);
240 dev->needed_headroom += sizeof(struct udphdr);
242 if (session->mtu != 0) {
243 dev->mtu = session->mtu;
244 dev->needed_headroom += session->hdr_len;
247 lock_sock(tunnel->sock);
248 l3_overhead = kernel_sock_ip_overhead(tunnel->sock);
249 release_sock(tunnel->sock);
250 if (l3_overhead == 0) {
251 /* L3 Overhead couldn't be identified, this could be
252 * because tunnel->sock was NULL or the socket's
253 * address family was not IPv4 or IPv6,
254 * dev mtu stays at 1500.
258 /* Adjust MTU, factor overhead - underlay L3, overlay L2 hdr
259 * UDP overhead, if any, was already factored in above.
261 overhead += session->hdr_len + ETH_HLEN + l3_overhead;
263 /* If PMTU discovery was enabled, use discovered MTU on L2TP device */
264 dst = sk_dst_get(tunnel->sock);
266 /* dst_mtu will use PMTU if found, else fallback to intf MTU */
267 u32 pmtu = dst_mtu(dst);
273 session->mtu = dev->mtu - overhead;
274 dev->mtu = session->mtu;
275 dev->needed_headroom += session->hdr_len;
278 static int l2tp_eth_create(struct net *net, struct l2tp_tunnel *tunnel,
279 u32 session_id, u32 peer_session_id,
280 struct l2tp_session_cfg *cfg)
282 unsigned char name_assign_type;
283 struct net_device *dev;
285 struct l2tp_session *session;
286 struct l2tp_eth *priv;
287 struct l2tp_eth_sess *spriv;
291 strlcpy(name, cfg->ifname, IFNAMSIZ);
292 name_assign_type = NET_NAME_USER;
294 strcpy(name, L2TP_ETH_DEV_NAME);
295 name_assign_type = NET_NAME_ENUM;
298 session = l2tp_session_create(sizeof(*spriv), tunnel, session_id,
299 peer_session_id, cfg);
300 if (IS_ERR(session)) {
301 rc = PTR_ERR(session);
305 dev = alloc_netdev(sizeof(*priv), name, name_assign_type,
312 dev_net_set(dev, net);
314 dev->max_mtu = ETH_MAX_MTU;
315 l2tp_eth_adjust_mtu(tunnel, session, dev);
317 priv = netdev_priv(dev);
319 priv->session = session;
321 priv->tunnel_sock = tunnel->sock;
322 session->recv_skb = l2tp_eth_dev_recv;
323 session->session_close = l2tp_eth_delete;
324 #if IS_ENABLED(CONFIG_L2TP_DEBUGFS)
325 session->show = l2tp_eth_show;
328 spriv = l2tp_session_priv(session);
330 l2tp_session_inc_refcount(session);
334 /* Register both device and session while holding the rtnl lock. This
335 * ensures that l2tp_eth_delete() will see that there's a device to
336 * unregister, even if it happened to run before we assign spriv->dev.
338 rc = l2tp_session_register(session, tunnel);
344 rc = register_netdevice(dev);
347 l2tp_session_delete(session);
348 l2tp_session_dec_refcount(session);
354 strlcpy(session->ifname, dev->name, IFNAMSIZ);
355 rcu_assign_pointer(spriv->dev, dev);
359 l2tp_session_dec_refcount(session);
361 __module_get(THIS_MODULE);
366 l2tp_session_dec_refcount(session);
375 static const struct l2tp_nl_cmd_ops l2tp_eth_nl_cmd_ops = {
376 .session_create = l2tp_eth_create,
377 .session_delete = l2tp_session_delete,
381 static int __init l2tp_eth_init(void)
385 err = l2tp_nl_register_ops(L2TP_PWTYPE_ETH, &l2tp_eth_nl_cmd_ops);
389 pr_info("L2TP ethernet pseudowire support (L2TPv3)\n");
397 static void __exit l2tp_eth_exit(void)
399 l2tp_nl_unregister_ops(L2TP_PWTYPE_ETH);
402 module_init(l2tp_eth_init);
403 module_exit(l2tp_eth_exit);
405 MODULE_LICENSE("GPL");
406 MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
407 MODULE_DESCRIPTION("L2TP ethernet pseudowire driver");
408 MODULE_VERSION("1.0");
409 MODULE_ALIAS_L2TP_PWTYPE(5);