1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* L2TPv3 ethernet pseudowire driver
4 * Copyright (c) 2008,2009,2010 Katalix Systems Ltd
7 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
9 #include <linux/module.h>
10 #include <linux/skbuff.h>
11 #include <linux/socket.h>
12 #include <linux/hash.h>
13 #include <linux/l2tp.h>
15 #include <linux/etherdevice.h>
16 #include <linux/spinlock.h>
21 #include <net/inet_common.h>
22 #include <net/inet_hashtables.h>
23 #include <net/tcp_states.h>
24 #include <net/protocol.h>
26 #include <net/net_namespace.h>
27 #include <net/netns/generic.h>
29 #include <linux/ipv6.h>
30 #include <linux/udp.h>
32 #include "l2tp_core.h"
34 /* Default device name. May be overridden by name specified by user */
35 #define L2TP_ETH_DEV_NAME "l2tpeth%d"
37 /* via netdev_priv() */
39 struct l2tp_session *session;
42 /* via l2tp_session_priv() */
43 struct l2tp_eth_sess {
44 struct net_device __rcu *dev;
47 static int l2tp_eth_dev_init(struct net_device *dev)
49 eth_hw_addr_random(dev);
50 eth_broadcast_addr(dev->broadcast);
51 netdev_lockdep_set_classes(dev);
56 static void l2tp_eth_dev_uninit(struct net_device *dev)
58 struct l2tp_eth *priv = netdev_priv(dev);
59 struct l2tp_eth_sess *spriv;
61 spriv = l2tp_session_priv(priv->session);
62 RCU_INIT_POINTER(spriv->dev, NULL);
63 /* No need for synchronize_net() here. We're called by
64 * unregister_netdev*(), which does the synchronisation for us.
68 static netdev_tx_t l2tp_eth_dev_xmit(struct sk_buff *skb, struct net_device *dev)
70 struct l2tp_eth *priv = netdev_priv(dev);
71 struct l2tp_session *session = priv->session;
72 unsigned int len = skb->len;
73 int ret = l2tp_xmit_skb(session, skb);
75 if (likely(ret == NET_XMIT_SUCCESS)) {
76 DEV_STATS_ADD(dev, tx_bytes, len);
77 DEV_STATS_INC(dev, tx_packets);
79 DEV_STATS_INC(dev, tx_dropped);
84 static void l2tp_eth_get_stats64(struct net_device *dev,
85 struct rtnl_link_stats64 *stats)
87 stats->tx_bytes = DEV_STATS_READ(dev, tx_bytes);
88 stats->tx_packets = DEV_STATS_READ(dev, tx_packets);
89 stats->tx_dropped = DEV_STATS_READ(dev, tx_dropped);
90 stats->rx_bytes = DEV_STATS_READ(dev, rx_bytes);
91 stats->rx_packets = DEV_STATS_READ(dev, rx_packets);
92 stats->rx_errors = DEV_STATS_READ(dev, rx_errors);
95 static const struct net_device_ops l2tp_eth_netdev_ops = {
96 .ndo_init = l2tp_eth_dev_init,
97 .ndo_uninit = l2tp_eth_dev_uninit,
98 .ndo_start_xmit = l2tp_eth_dev_xmit,
99 .ndo_get_stats64 = l2tp_eth_get_stats64,
100 .ndo_set_mac_address = eth_mac_addr,
103 static struct device_type l2tpeth_type = {
107 static void l2tp_eth_dev_setup(struct net_device *dev)
109 SET_NETDEV_DEVTYPE(dev, &l2tpeth_type);
111 dev->priv_flags &= ~IFF_TX_SKB_SHARING;
112 dev->features |= NETIF_F_LLTX;
113 dev->netdev_ops = &l2tp_eth_netdev_ops;
114 dev->needs_free_netdev = true;
117 static void l2tp_eth_dev_recv(struct l2tp_session *session, struct sk_buff *skb, int data_len)
119 struct l2tp_eth_sess *spriv = l2tp_session_priv(session);
120 struct net_device *dev;
122 if (!pskb_may_pull(skb, ETH_HLEN))
127 /* checksums verified by L2TP */
128 skb->ip_summed = CHECKSUM_NONE;
134 dev = rcu_dereference(spriv->dev);
138 if (dev_forward_skb(dev, skb) == NET_RX_SUCCESS) {
139 DEV_STATS_INC(dev, rx_packets);
140 DEV_STATS_ADD(dev, rx_bytes, data_len);
142 DEV_STATS_INC(dev, rx_errors);
154 static void l2tp_eth_delete(struct l2tp_session *session)
156 struct l2tp_eth_sess *spriv;
157 struct net_device *dev;
160 spriv = l2tp_session_priv(session);
163 dev = rtnl_dereference(spriv->dev);
165 unregister_netdevice(dev);
167 module_put(THIS_MODULE);
174 static void l2tp_eth_show(struct seq_file *m, void *arg)
176 struct l2tp_session *session = arg;
177 struct l2tp_eth_sess *spriv = l2tp_session_priv(session);
178 struct net_device *dev;
181 dev = rcu_dereference(spriv->dev);
189 seq_printf(m, " interface %s\n", dev->name);
194 static void l2tp_eth_adjust_mtu(struct l2tp_tunnel *tunnel,
195 struct l2tp_session *session,
196 struct net_device *dev)
198 unsigned int overhead = 0;
202 /* if the encap is UDP, account for UDP header size */
203 if (tunnel->encap == L2TP_ENCAPTYPE_UDP) {
204 overhead += sizeof(struct udphdr);
205 dev->needed_headroom += sizeof(struct udphdr);
208 lock_sock(tunnel->sock);
209 l3_overhead = kernel_sock_ip_overhead(tunnel->sock);
210 release_sock(tunnel->sock);
212 if (l3_overhead == 0) {
213 /* L3 Overhead couldn't be identified, this could be
214 * because tunnel->sock was NULL or the socket's
215 * address family was not IPv4 or IPv6,
216 * dev mtu stays at 1500.
220 /* Adjust MTU, factor overhead - underlay L3, overlay L2 hdr
221 * UDP overhead, if any, was already factored in above.
223 overhead += session->hdr_len + ETH_HLEN + l3_overhead;
225 mtu = l2tp_tunnel_dst_mtu(tunnel) - overhead;
226 if (mtu < dev->min_mtu || mtu > dev->max_mtu)
227 dev->mtu = ETH_DATA_LEN - overhead;
231 dev->needed_headroom += session->hdr_len;
234 static int l2tp_eth_create(struct net *net, struct l2tp_tunnel *tunnel,
235 u32 session_id, u32 peer_session_id,
236 struct l2tp_session_cfg *cfg)
238 unsigned char name_assign_type;
239 struct net_device *dev;
241 struct l2tp_session *session;
242 struct l2tp_eth *priv;
243 struct l2tp_eth_sess *spriv;
247 strscpy(name, cfg->ifname, IFNAMSIZ);
248 name_assign_type = NET_NAME_USER;
250 strcpy(name, L2TP_ETH_DEV_NAME);
251 name_assign_type = NET_NAME_ENUM;
254 session = l2tp_session_create(sizeof(*spriv), tunnel, session_id,
255 peer_session_id, cfg);
256 if (IS_ERR(session)) {
257 rc = PTR_ERR(session);
261 dev = alloc_netdev(sizeof(*priv), name, name_assign_type,
268 dev_net_set(dev, net);
270 dev->max_mtu = ETH_MAX_MTU;
271 l2tp_eth_adjust_mtu(tunnel, session, dev);
273 priv = netdev_priv(dev);
274 priv->session = session;
276 session->recv_skb = l2tp_eth_dev_recv;
277 session->session_close = l2tp_eth_delete;
278 if (IS_ENABLED(CONFIG_L2TP_DEBUGFS))
279 session->show = l2tp_eth_show;
281 spriv = l2tp_session_priv(session);
283 l2tp_session_inc_refcount(session);
287 /* Register both device and session while holding the rtnl lock. This
288 * ensures that l2tp_eth_delete() will see that there's a device to
289 * unregister, even if it happened to run before we assign spriv->dev.
291 rc = l2tp_session_register(session, tunnel);
297 rc = register_netdevice(dev);
300 l2tp_session_delete(session);
301 l2tp_session_dec_refcount(session);
307 strscpy(session->ifname, dev->name, IFNAMSIZ);
308 rcu_assign_pointer(spriv->dev, dev);
312 l2tp_session_dec_refcount(session);
314 __module_get(THIS_MODULE);
319 l2tp_session_dec_refcount(session);
327 static const struct l2tp_nl_cmd_ops l2tp_eth_nl_cmd_ops = {
328 .session_create = l2tp_eth_create,
329 .session_delete = l2tp_session_delete,
332 static int __init l2tp_eth_init(void)
336 err = l2tp_nl_register_ops(L2TP_PWTYPE_ETH, &l2tp_eth_nl_cmd_ops);
340 pr_info("L2TP ethernet pseudowire support (L2TPv3)\n");
348 static void __exit l2tp_eth_exit(void)
350 l2tp_nl_unregister_ops(L2TP_PWTYPE_ETH);
353 module_init(l2tp_eth_init);
354 module_exit(l2tp_eth_exit);
356 MODULE_LICENSE("GPL");
357 MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
358 MODULE_DESCRIPTION("L2TP ethernet pseudowire driver");
359 MODULE_VERSION("1.0");
360 MODULE_ALIAS_L2TP_PWTYPE(5);