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 *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)
78 static int l2tp_eth_dev_xmit(struct sk_buff *skb, struct net_device *dev)
80 struct l2tp_eth *priv = netdev_priv(dev);
81 struct l2tp_session *session = priv->session;
82 unsigned int len = skb->len;
83 int ret = l2tp_xmit_skb(session, skb, session->hdr_len);
85 if (likely(ret == NET_XMIT_SUCCESS)) {
86 atomic_long_add(len, &priv->tx_bytes);
87 atomic_long_inc(&priv->tx_packets);
89 atomic_long_inc(&priv->tx_dropped);
94 static void l2tp_eth_get_stats64(struct net_device *dev,
95 struct rtnl_link_stats64 *stats)
97 struct l2tp_eth *priv = netdev_priv(dev);
99 stats->tx_bytes = (unsigned long) atomic_long_read(&priv->tx_bytes);
100 stats->tx_packets = (unsigned long) atomic_long_read(&priv->tx_packets);
101 stats->tx_dropped = (unsigned long) atomic_long_read(&priv->tx_dropped);
102 stats->rx_bytes = (unsigned long) atomic_long_read(&priv->rx_bytes);
103 stats->rx_packets = (unsigned long) atomic_long_read(&priv->rx_packets);
104 stats->rx_errors = (unsigned long) atomic_long_read(&priv->rx_errors);
108 static const struct net_device_ops l2tp_eth_netdev_ops = {
109 .ndo_init = l2tp_eth_dev_init,
110 .ndo_uninit = l2tp_eth_dev_uninit,
111 .ndo_start_xmit = l2tp_eth_dev_xmit,
112 .ndo_get_stats64 = l2tp_eth_get_stats64,
113 .ndo_set_mac_address = eth_mac_addr,
116 static struct device_type l2tpeth_type = {
120 static void l2tp_eth_dev_setup(struct net_device *dev)
122 SET_NETDEV_DEVTYPE(dev, &l2tpeth_type);
124 dev->priv_flags &= ~IFF_TX_SKB_SHARING;
125 dev->features |= NETIF_F_LLTX;
126 dev->netdev_ops = &l2tp_eth_netdev_ops;
127 dev->needs_free_netdev = true;
130 static void l2tp_eth_dev_recv(struct l2tp_session *session, struct sk_buff *skb, int data_len)
132 struct l2tp_eth_sess *spriv = l2tp_session_priv(session);
133 struct net_device *dev = spriv->dev;
134 struct l2tp_eth *priv = netdev_priv(dev);
136 if (session->debug & L2TP_MSG_DATA) {
139 length = min(32u, skb->len);
140 if (!pskb_may_pull(skb, length))
143 pr_debug("%s: eth recv\n", session->name);
144 print_hex_dump_bytes("", DUMP_PREFIX_OFFSET, skb->data, length);
147 if (!pskb_may_pull(skb, ETH_HLEN))
152 /* checksums verified by L2TP */
153 skb->ip_summed = CHECKSUM_NONE;
158 if (dev_forward_skb(dev, skb) == NET_RX_SUCCESS) {
159 atomic_long_inc(&priv->rx_packets);
160 atomic_long_add(data_len, &priv->rx_bytes);
162 atomic_long_inc(&priv->rx_errors);
167 atomic_long_inc(&priv->rx_errors);
171 static void l2tp_eth_delete(struct l2tp_session *session)
173 struct l2tp_eth_sess *spriv;
174 struct net_device *dev;
177 spriv = l2tp_session_priv(session);
180 unregister_netdev(dev);
182 module_put(THIS_MODULE);
187 #if IS_ENABLED(CONFIG_L2TP_DEBUGFS)
188 static void l2tp_eth_show(struct seq_file *m, void *arg)
190 struct l2tp_session *session = arg;
191 struct l2tp_eth_sess *spriv = l2tp_session_priv(session);
192 struct net_device *dev = spriv->dev;
194 seq_printf(m, " interface %s\n", dev->name);
198 static void l2tp_eth_adjust_mtu(struct l2tp_tunnel *tunnel,
199 struct l2tp_session *session,
200 struct net_device *dev)
202 unsigned int overhead = 0;
203 struct dst_entry *dst;
206 /* if the encap is UDP, account for UDP header size */
207 if (tunnel->encap == L2TP_ENCAPTYPE_UDP) {
208 overhead += sizeof(struct udphdr);
209 dev->needed_headroom += sizeof(struct udphdr);
211 if (session->mtu != 0) {
212 dev->mtu = session->mtu;
213 dev->needed_headroom += session->hdr_len;
216 lock_sock(tunnel->sock);
217 l3_overhead = kernel_sock_ip_overhead(tunnel->sock);
218 release_sock(tunnel->sock);
219 if (l3_overhead == 0) {
220 /* L3 Overhead couldn't be identified, this could be
221 * because tunnel->sock was NULL or the socket's
222 * address family was not IPv4 or IPv6,
223 * dev mtu stays at 1500.
227 /* Adjust MTU, factor overhead - underlay L3, overlay L2 hdr
228 * UDP overhead, if any, was already factored in above.
230 overhead += session->hdr_len + ETH_HLEN + l3_overhead;
232 /* If PMTU discovery was enabled, use discovered MTU on L2TP device */
233 dst = sk_dst_get(tunnel->sock);
235 /* dst_mtu will use PMTU if found, else fallback to intf MTU */
236 u32 pmtu = dst_mtu(dst);
242 session->mtu = dev->mtu - overhead;
243 dev->mtu = session->mtu;
244 dev->needed_headroom += session->hdr_len;
247 static int l2tp_eth_create(struct net *net, struct l2tp_tunnel *tunnel,
248 u32 session_id, u32 peer_session_id,
249 struct l2tp_session_cfg *cfg)
251 unsigned char name_assign_type;
252 struct net_device *dev;
254 struct l2tp_session *session;
255 struct l2tp_eth *priv;
256 struct l2tp_eth_sess *spriv;
260 strlcpy(name, cfg->ifname, IFNAMSIZ);
261 name_assign_type = NET_NAME_USER;
263 strcpy(name, L2TP_ETH_DEV_NAME);
264 name_assign_type = NET_NAME_ENUM;
267 session = l2tp_session_create(sizeof(*spriv), tunnel, session_id,
268 peer_session_id, cfg);
269 if (IS_ERR(session)) {
270 rc = PTR_ERR(session);
274 l2tp_session_inc_refcount(session);
275 rc = l2tp_session_register(session, tunnel);
281 dev = alloc_netdev(sizeof(*priv), name, name_assign_type,
285 goto out_del_session;
288 dev_net_set(dev, net);
290 dev->max_mtu = ETH_MAX_MTU;
291 l2tp_eth_adjust_mtu(tunnel, session, dev);
293 priv = netdev_priv(dev);
295 priv->session = session;
297 priv->tunnel_sock = tunnel->sock;
298 session->recv_skb = l2tp_eth_dev_recv;
299 session->session_close = l2tp_eth_delete;
300 #if IS_ENABLED(CONFIG_L2TP_DEBUGFS)
301 session->show = l2tp_eth_show;
304 spriv = l2tp_session_priv(session);
307 rc = register_netdev(dev);
311 __module_get(THIS_MODULE);
312 /* Must be done after register_netdev() */
313 strlcpy(session->ifname, dev->name, IFNAMSIZ);
314 l2tp_session_dec_refcount(session);
324 l2tp_session_delete(session);
325 l2tp_session_dec_refcount(session);
331 static const struct l2tp_nl_cmd_ops l2tp_eth_nl_cmd_ops = {
332 .session_create = l2tp_eth_create,
333 .session_delete = l2tp_session_delete,
337 static int __init l2tp_eth_init(void)
341 err = l2tp_nl_register_ops(L2TP_PWTYPE_ETH, &l2tp_eth_nl_cmd_ops);
345 pr_info("L2TP ethernet pseudowire support (L2TPv3)\n");
353 static void __exit l2tp_eth_exit(void)
355 l2tp_nl_unregister_ops(L2TP_PWTYPE_ETH);
358 module_init(l2tp_eth_init);
359 module_exit(l2tp_eth_exit);
361 MODULE_LICENSE("GPL");
362 MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
363 MODULE_DESCRIPTION("L2TP ethernet pseudowire driver");
364 MODULE_VERSION("1.0");
365 MODULE_ALIAS_L2TP_PWTYPE(5);