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 struct rtnl_link_stats64 *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 = atomic_long_read(&priv->tx_bytes);
107 stats->tx_packets = atomic_long_read(&priv->tx_packets);
108 stats->tx_dropped = atomic_long_read(&priv->tx_dropped);
109 stats->rx_bytes = atomic_long_read(&priv->rx_bytes);
110 stats->rx_packets = atomic_long_read(&priv->rx_packets);
111 stats->rx_errors = atomic_long_read(&priv->rx_errors);
116 static const struct net_device_ops l2tp_eth_netdev_ops = {
117 .ndo_init = l2tp_eth_dev_init,
118 .ndo_uninit = l2tp_eth_dev_uninit,
119 .ndo_start_xmit = l2tp_eth_dev_xmit,
120 .ndo_get_stats64 = l2tp_eth_get_stats64,
121 .ndo_set_mac_address = eth_mac_addr,
124 static void l2tp_eth_dev_setup(struct net_device *dev)
127 dev->priv_flags &= ~IFF_TX_SKB_SHARING;
128 dev->features |= NETIF_F_LLTX;
129 dev->netdev_ops = &l2tp_eth_netdev_ops;
130 dev->destructor = free_netdev;
133 static void l2tp_eth_dev_recv(struct l2tp_session *session, struct sk_buff *skb, int data_len)
135 struct l2tp_eth_sess *spriv = l2tp_session_priv(session);
136 struct net_device *dev;
137 struct l2tp_eth *priv;
139 if (session->debug & L2TP_MSG_DATA) {
142 length = min(32u, skb->len);
143 if (!pskb_may_pull(skb, length))
146 pr_debug("%s: eth recv\n", session->name);
147 print_hex_dump_bytes("", DUMP_PREFIX_OFFSET, skb->data, length);
150 if (!pskb_may_pull(skb, ETH_HLEN))
155 /* checksums verified by L2TP */
156 skb->ip_summed = CHECKSUM_NONE;
162 dev = rcu_dereference(spriv->dev);
166 priv = netdev_priv(dev);
167 if (dev_forward_skb(dev, skb) == NET_RX_SUCCESS) {
168 atomic_long_inc(&priv->rx_packets);
169 atomic_long_add(data_len, &priv->rx_bytes);
171 atomic_long_inc(&priv->rx_errors);
183 static void l2tp_eth_delete(struct l2tp_session *session)
185 struct l2tp_eth_sess *spriv;
186 struct net_device *dev;
189 spriv = l2tp_session_priv(session);
192 dev = rtnl_dereference(spriv->dev);
194 unregister_netdevice(dev);
196 module_put(THIS_MODULE);
203 #if IS_ENABLED(CONFIG_L2TP_DEBUGFS)
204 static void l2tp_eth_show(struct seq_file *m, void *arg)
206 struct l2tp_session *session = arg;
207 struct l2tp_eth_sess *spriv = l2tp_session_priv(session);
208 struct net_device *dev;
211 dev = rcu_dereference(spriv->dev);
219 seq_printf(m, " interface %s\n", dev->name);
225 static void l2tp_eth_adjust_mtu(struct l2tp_tunnel *tunnel,
226 struct l2tp_session *session,
227 struct net_device *dev)
229 unsigned int overhead = 0;
230 struct dst_entry *dst;
233 /* if the encap is UDP, account for UDP header size */
234 if (tunnel->encap == L2TP_ENCAPTYPE_UDP) {
235 overhead += sizeof(struct udphdr);
236 dev->needed_headroom += sizeof(struct udphdr);
238 if (session->mtu != 0) {
239 dev->mtu = session->mtu;
240 dev->needed_headroom += session->hdr_len;
243 lock_sock(tunnel->sock);
244 l3_overhead = kernel_sock_ip_overhead(tunnel->sock);
245 release_sock(tunnel->sock);
246 if (l3_overhead == 0) {
247 /* L3 Overhead couldn't be identified, this could be
248 * because tunnel->sock was NULL or the socket's
249 * address family was not IPv4 or IPv6,
250 * dev mtu stays at 1500.
254 /* Adjust MTU, factor overhead - underlay L3, overlay L2 hdr
255 * UDP overhead, if any, was already factored in above.
257 overhead += session->hdr_len + ETH_HLEN + l3_overhead;
259 /* If PMTU discovery was enabled, use discovered MTU on L2TP device */
260 dst = sk_dst_get(tunnel->sock);
262 /* dst_mtu will use PMTU if found, else fallback to intf MTU */
263 u32 pmtu = dst_mtu(dst);
269 session->mtu = dev->mtu - overhead;
270 dev->mtu = session->mtu;
271 dev->needed_headroom += session->hdr_len;
274 static int l2tp_eth_create(struct net *net, struct l2tp_tunnel *tunnel,
275 u32 session_id, u32 peer_session_id,
276 struct l2tp_session_cfg *cfg)
278 struct net_device *dev;
280 struct l2tp_session *session;
281 struct l2tp_eth *priv;
282 struct l2tp_eth_sess *spriv;
286 dev = dev_get_by_name(net, cfg->ifname);
292 strlcpy(name, cfg->ifname, IFNAMSIZ);
294 strcpy(name, L2TP_ETH_DEV_NAME);
296 session = l2tp_session_create(sizeof(*spriv), tunnel, session_id,
297 peer_session_id, cfg);
298 if (IS_ERR(session)) {
299 rc = PTR_ERR(session);
303 dev = alloc_netdev(sizeof(*priv), name, NET_NAME_UNKNOWN,
310 dev_net_set(dev, net);
311 l2tp_eth_adjust_mtu(tunnel, session, dev);
313 priv = netdev_priv(dev);
315 priv->session = session;
317 priv->tunnel_sock = tunnel->sock;
318 session->recv_skb = l2tp_eth_dev_recv;
319 session->session_close = l2tp_eth_delete;
320 #if IS_ENABLED(CONFIG_L2TP_DEBUGFS)
321 session->show = l2tp_eth_show;
324 spriv = l2tp_session_priv(session);
326 l2tp_session_inc_refcount(session);
330 /* Register both device and session while holding the rtnl lock. This
331 * ensures that l2tp_eth_delete() will see that there's a device to
332 * unregister, even if it happened to run before we assign spriv->dev.
334 rc = l2tp_session_register(session, tunnel);
340 rc = register_netdevice(dev);
343 l2tp_session_delete(session);
344 l2tp_session_dec_refcount(session);
350 strlcpy(session->ifname, dev->name, IFNAMSIZ);
351 rcu_assign_pointer(spriv->dev, dev);
355 l2tp_session_dec_refcount(session);
357 __module_get(THIS_MODULE);
362 l2tp_session_dec_refcount(session);
371 static const struct l2tp_nl_cmd_ops l2tp_eth_nl_cmd_ops = {
372 .session_create = l2tp_eth_create,
373 .session_delete = l2tp_session_delete,
377 static int __init l2tp_eth_init(void)
381 err = l2tp_nl_register_ops(L2TP_PWTYPE_ETH, &l2tp_eth_nl_cmd_ops);
385 pr_info("L2TP ethernet pseudowire support (L2TPv3)\n");
393 static void __exit l2tp_eth_exit(void)
395 l2tp_nl_unregister_ops(L2TP_PWTYPE_ETH);
398 module_init(l2tp_eth_init);
399 module_exit(l2tp_eth_exit);
401 MODULE_LICENSE("GPL");
402 MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
403 MODULE_DESCRIPTION("L2TP ethernet pseudowire driver");
404 MODULE_VERSION("1.0");
405 MODULE_ALIAS_L2TP_PWTYPE(5);