1 // SPDX-License-Identifier: GPL-2.0-or-later
3 * L2TPv3 ethernet pseudowire driver
5 * Copyright (c) 2008,2009,2010 Katalix Systems Ltd
8 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
10 #include <linux/module.h>
11 #include <linux/skbuff.h>
12 #include <linux/socket.h>
13 #include <linux/hash.h>
14 #include <linux/l2tp.h>
16 #include <linux/etherdevice.h>
17 #include <linux/spinlock.h>
22 #include <net/inet_common.h>
23 #include <net/inet_hashtables.h>
24 #include <net/tcp_states.h>
25 #include <net/protocol.h>
27 #include <net/net_namespace.h>
28 #include <net/netns/generic.h>
30 #include <linux/ipv6.h>
31 #include <linux/udp.h>
33 #include "l2tp_core.h"
35 /* Default device name. May be overridden by name specified by user */
36 #define L2TP_ETH_DEV_NAME "l2tpeth%d"
38 /* via netdev_priv() */
40 struct l2tp_session *session;
41 atomic_long_t tx_bytes;
42 atomic_long_t tx_packets;
43 atomic_long_t tx_dropped;
44 atomic_long_t rx_bytes;
45 atomic_long_t rx_packets;
46 atomic_long_t rx_errors;
49 /* via l2tp_session_priv() */
50 struct l2tp_eth_sess {
51 struct net_device __rcu *dev;
55 static int l2tp_eth_dev_init(struct net_device *dev)
57 eth_hw_addr_random(dev);
58 eth_broadcast_addr(dev->broadcast);
59 netdev_lockdep_set_classes(dev);
64 static void l2tp_eth_dev_uninit(struct net_device *dev)
66 struct l2tp_eth *priv = netdev_priv(dev);
67 struct l2tp_eth_sess *spriv;
69 spriv = l2tp_session_priv(priv->session);
70 RCU_INIT_POINTER(spriv->dev, NULL);
71 /* No need for synchronize_net() here. We're called by
72 * unregister_netdev*(), which does the synchronisation for us.
76 static int l2tp_eth_dev_xmit(struct sk_buff *skb, struct net_device *dev)
78 struct l2tp_eth *priv = netdev_priv(dev);
79 struct l2tp_session *session = priv->session;
80 unsigned int len = skb->len;
81 int ret = l2tp_xmit_skb(session, skb, session->hdr_len);
83 if (likely(ret == NET_XMIT_SUCCESS)) {
84 atomic_long_add(len, &priv->tx_bytes);
85 atomic_long_inc(&priv->tx_packets);
87 atomic_long_inc(&priv->tx_dropped);
92 static void l2tp_eth_get_stats64(struct net_device *dev,
93 struct rtnl_link_stats64 *stats)
95 struct l2tp_eth *priv = netdev_priv(dev);
97 stats->tx_bytes = (unsigned long) atomic_long_read(&priv->tx_bytes);
98 stats->tx_packets = (unsigned long) atomic_long_read(&priv->tx_packets);
99 stats->tx_dropped = (unsigned long) atomic_long_read(&priv->tx_dropped);
100 stats->rx_bytes = (unsigned long) atomic_long_read(&priv->rx_bytes);
101 stats->rx_packets = (unsigned long) atomic_long_read(&priv->rx_packets);
102 stats->rx_errors = (unsigned long) atomic_long_read(&priv->rx_errors);
106 static const struct net_device_ops l2tp_eth_netdev_ops = {
107 .ndo_init = l2tp_eth_dev_init,
108 .ndo_uninit = l2tp_eth_dev_uninit,
109 .ndo_start_xmit = l2tp_eth_dev_xmit,
110 .ndo_get_stats64 = l2tp_eth_get_stats64,
111 .ndo_set_mac_address = eth_mac_addr,
114 static struct device_type l2tpeth_type = {
118 static void l2tp_eth_dev_setup(struct net_device *dev)
120 SET_NETDEV_DEVTYPE(dev, &l2tpeth_type);
122 dev->priv_flags &= ~IFF_TX_SKB_SHARING;
123 dev->features |= NETIF_F_LLTX;
124 dev->netdev_ops = &l2tp_eth_netdev_ops;
125 dev->needs_free_netdev = true;
128 static void l2tp_eth_dev_recv(struct l2tp_session *session, struct sk_buff *skb, int data_len)
130 struct l2tp_eth_sess *spriv = l2tp_session_priv(session);
131 struct net_device *dev;
132 struct l2tp_eth *priv;
134 if (session->debug & L2TP_MSG_DATA) {
137 length = min(32u, skb->len);
138 if (!pskb_may_pull(skb, length))
141 pr_debug("%s: eth recv\n", session->name);
142 print_hex_dump_bytes("", DUMP_PREFIX_OFFSET, skb->data, length);
145 if (!pskb_may_pull(skb, ETH_HLEN))
150 /* checksums verified by L2TP */
151 skb->ip_summed = CHECKSUM_NONE;
157 dev = rcu_dereference(spriv->dev);
161 priv = netdev_priv(dev);
162 if (dev_forward_skb(dev, skb) == NET_RX_SUCCESS) {
163 atomic_long_inc(&priv->rx_packets);
164 atomic_long_add(data_len, &priv->rx_bytes);
166 atomic_long_inc(&priv->rx_errors);
178 static void l2tp_eth_delete(struct l2tp_session *session)
180 struct l2tp_eth_sess *spriv;
181 struct net_device *dev;
184 spriv = l2tp_session_priv(session);
187 dev = rtnl_dereference(spriv->dev);
189 unregister_netdevice(dev);
191 module_put(THIS_MODULE);
198 static void l2tp_eth_show(struct seq_file *m, void *arg)
200 struct l2tp_session *session = arg;
201 struct l2tp_eth_sess *spriv = l2tp_session_priv(session);
202 struct net_device *dev;
205 dev = rcu_dereference(spriv->dev);
213 seq_printf(m, " interface %s\n", dev->name);
218 static void l2tp_eth_adjust_mtu(struct l2tp_tunnel *tunnel,
219 struct l2tp_session *session,
220 struct net_device *dev)
222 unsigned int overhead = 0;
226 /* if the encap is UDP, account for UDP header size */
227 if (tunnel->encap == L2TP_ENCAPTYPE_UDP) {
228 overhead += sizeof(struct udphdr);
229 dev->needed_headroom += sizeof(struct udphdr);
232 lock_sock(tunnel->sock);
233 l3_overhead = kernel_sock_ip_overhead(tunnel->sock);
234 release_sock(tunnel->sock);
236 if (l3_overhead == 0) {
237 /* L3 Overhead couldn't be identified, this could be
238 * because tunnel->sock was NULL or the socket's
239 * address family was not IPv4 or IPv6,
240 * dev mtu stays at 1500.
244 /* Adjust MTU, factor overhead - underlay L3, overlay L2 hdr
245 * UDP overhead, if any, was already factored in above.
247 overhead += session->hdr_len + ETH_HLEN + l3_overhead;
249 mtu = l2tp_tunnel_dst_mtu(tunnel) - overhead;
250 if (mtu < dev->min_mtu || mtu > dev->max_mtu)
251 dev->mtu = ETH_DATA_LEN - overhead;
255 dev->needed_headroom += session->hdr_len;
258 static int l2tp_eth_create(struct net *net, struct l2tp_tunnel *tunnel,
259 u32 session_id, u32 peer_session_id,
260 struct l2tp_session_cfg *cfg)
262 unsigned char name_assign_type;
263 struct net_device *dev;
265 struct l2tp_session *session;
266 struct l2tp_eth *priv;
267 struct l2tp_eth_sess *spriv;
271 strlcpy(name, cfg->ifname, IFNAMSIZ);
272 name_assign_type = NET_NAME_USER;
274 strcpy(name, L2TP_ETH_DEV_NAME);
275 name_assign_type = NET_NAME_ENUM;
278 session = l2tp_session_create(sizeof(*spriv), tunnel, session_id,
279 peer_session_id, cfg);
280 if (IS_ERR(session)) {
281 rc = PTR_ERR(session);
285 dev = alloc_netdev(sizeof(*priv), name, name_assign_type,
292 dev_net_set(dev, net);
294 dev->max_mtu = ETH_MAX_MTU;
295 l2tp_eth_adjust_mtu(tunnel, session, dev);
297 priv = netdev_priv(dev);
298 priv->session = session;
300 session->recv_skb = l2tp_eth_dev_recv;
301 session->session_close = l2tp_eth_delete;
302 if (IS_ENABLED(CONFIG_L2TP_DEBUGFS))
303 session->show = l2tp_eth_show;
305 spriv = l2tp_session_priv(session);
307 l2tp_session_inc_refcount(session);
311 /* Register both device and session while holding the rtnl lock. This
312 * ensures that l2tp_eth_delete() will see that there's a device to
313 * unregister, even if it happened to run before we assign spriv->dev.
315 rc = l2tp_session_register(session, tunnel);
321 rc = register_netdevice(dev);
324 l2tp_session_delete(session);
325 l2tp_session_dec_refcount(session);
331 strlcpy(session->ifname, dev->name, IFNAMSIZ);
332 rcu_assign_pointer(spriv->dev, dev);
336 l2tp_session_dec_refcount(session);
338 __module_get(THIS_MODULE);
343 l2tp_session_dec_refcount(session);
352 static const struct l2tp_nl_cmd_ops l2tp_eth_nl_cmd_ops = {
353 .session_create = l2tp_eth_create,
354 .session_delete = l2tp_session_delete,
358 static int __init l2tp_eth_init(void)
362 err = l2tp_nl_register_ops(L2TP_PWTYPE_ETH, &l2tp_eth_nl_cmd_ops);
366 pr_info("L2TP ethernet pseudowire support (L2TPv3)\n");
374 static void __exit l2tp_eth_exit(void)
376 l2tp_nl_unregister_ops(L2TP_PWTYPE_ETH);
379 module_init(l2tp_eth_init);
380 module_exit(l2tp_eth_exit);
382 MODULE_LICENSE("GPL");
383 MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
384 MODULE_DESCRIPTION("L2TP ethernet pseudowire driver");
385 MODULE_VERSION("1.0");
386 MODULE_ALIAS_L2TP_PWTYPE(5);