/net/l2tp/l2tp_eth.c

http://github.com/mirrors/linux · C · 385 lines · 285 code · 74 blank · 26 comment · 28 complexity · 67de501741fedf5a349b709b56a9013c MD5 · raw file

  1. // SPDX-License-Identifier: GPL-2.0-or-later
  2. /*
  3. * L2TPv3 ethernet pseudowire driver
  4. *
  5. * Copyright (c) 2008,2009,2010 Katalix Systems Ltd
  6. */
  7. #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  8. #include <linux/module.h>
  9. #include <linux/skbuff.h>
  10. #include <linux/socket.h>
  11. #include <linux/hash.h>
  12. #include <linux/l2tp.h>
  13. #include <linux/in.h>
  14. #include <linux/etherdevice.h>
  15. #include <linux/spinlock.h>
  16. #include <net/sock.h>
  17. #include <net/ip.h>
  18. #include <net/icmp.h>
  19. #include <net/udp.h>
  20. #include <net/inet_common.h>
  21. #include <net/inet_hashtables.h>
  22. #include <net/tcp_states.h>
  23. #include <net/protocol.h>
  24. #include <net/xfrm.h>
  25. #include <net/net_namespace.h>
  26. #include <net/netns/generic.h>
  27. #include <linux/ip.h>
  28. #include <linux/ipv6.h>
  29. #include <linux/udp.h>
  30. #include "l2tp_core.h"
  31. /* Default device name. May be overridden by name specified by user */
  32. #define L2TP_ETH_DEV_NAME "l2tpeth%d"
  33. /* via netdev_priv() */
  34. struct l2tp_eth {
  35. struct l2tp_session *session;
  36. atomic_long_t tx_bytes;
  37. atomic_long_t tx_packets;
  38. atomic_long_t tx_dropped;
  39. atomic_long_t rx_bytes;
  40. atomic_long_t rx_packets;
  41. atomic_long_t rx_errors;
  42. };
  43. /* via l2tp_session_priv() */
  44. struct l2tp_eth_sess {
  45. struct net_device __rcu *dev;
  46. };
  47. static int l2tp_eth_dev_init(struct net_device *dev)
  48. {
  49. eth_hw_addr_random(dev);
  50. eth_broadcast_addr(dev->broadcast);
  51. return 0;
  52. }
  53. static void l2tp_eth_dev_uninit(struct net_device *dev)
  54. {
  55. struct l2tp_eth *priv = netdev_priv(dev);
  56. struct l2tp_eth_sess *spriv;
  57. spriv = l2tp_session_priv(priv->session);
  58. RCU_INIT_POINTER(spriv->dev, NULL);
  59. /* No need for synchronize_net() here. We're called by
  60. * unregister_netdev*(), which does the synchronisation for us.
  61. */
  62. }
  63. static int l2tp_eth_dev_xmit(struct sk_buff *skb, struct net_device *dev)
  64. {
  65. struct l2tp_eth *priv = netdev_priv(dev);
  66. struct l2tp_session *session = priv->session;
  67. unsigned int len = skb->len;
  68. int ret = l2tp_xmit_skb(session, skb, session->hdr_len);
  69. if (likely(ret == NET_XMIT_SUCCESS)) {
  70. atomic_long_add(len, &priv->tx_bytes);
  71. atomic_long_inc(&priv->tx_packets);
  72. } else {
  73. atomic_long_inc(&priv->tx_dropped);
  74. }
  75. return NETDEV_TX_OK;
  76. }
  77. static void l2tp_eth_get_stats64(struct net_device *dev,
  78. struct rtnl_link_stats64 *stats)
  79. {
  80. struct l2tp_eth *priv = netdev_priv(dev);
  81. stats->tx_bytes = (unsigned long) atomic_long_read(&priv->tx_bytes);
  82. stats->tx_packets = (unsigned long) atomic_long_read(&priv->tx_packets);
  83. stats->tx_dropped = (unsigned long) atomic_long_read(&priv->tx_dropped);
  84. stats->rx_bytes = (unsigned long) atomic_long_read(&priv->rx_bytes);
  85. stats->rx_packets = (unsigned long) atomic_long_read(&priv->rx_packets);
  86. stats->rx_errors = (unsigned long) atomic_long_read(&priv->rx_errors);
  87. }
  88. static const struct net_device_ops l2tp_eth_netdev_ops = {
  89. .ndo_init = l2tp_eth_dev_init,
  90. .ndo_uninit = l2tp_eth_dev_uninit,
  91. .ndo_start_xmit = l2tp_eth_dev_xmit,
  92. .ndo_get_stats64 = l2tp_eth_get_stats64,
  93. .ndo_set_mac_address = eth_mac_addr,
  94. };
  95. static struct device_type l2tpeth_type = {
  96. .name = "l2tpeth",
  97. };
  98. static void l2tp_eth_dev_setup(struct net_device *dev)
  99. {
  100. SET_NETDEV_DEVTYPE(dev, &l2tpeth_type);
  101. ether_setup(dev);
  102. dev->priv_flags &= ~IFF_TX_SKB_SHARING;
  103. dev->features |= NETIF_F_LLTX;
  104. dev->netdev_ops = &l2tp_eth_netdev_ops;
  105. dev->needs_free_netdev = true;
  106. }
  107. static void l2tp_eth_dev_recv(struct l2tp_session *session, struct sk_buff *skb, int data_len)
  108. {
  109. struct l2tp_eth_sess *spriv = l2tp_session_priv(session);
  110. struct net_device *dev;
  111. struct l2tp_eth *priv;
  112. if (session->debug & L2TP_MSG_DATA) {
  113. unsigned int length;
  114. length = min(32u, skb->len);
  115. if (!pskb_may_pull(skb, length))
  116. goto error;
  117. pr_debug("%s: eth recv\n", session->name);
  118. print_hex_dump_bytes("", DUMP_PREFIX_OFFSET, skb->data, length);
  119. }
  120. if (!pskb_may_pull(skb, ETH_HLEN))
  121. goto error;
  122. secpath_reset(skb);
  123. /* checksums verified by L2TP */
  124. skb->ip_summed = CHECKSUM_NONE;
  125. skb_dst_drop(skb);
  126. nf_reset_ct(skb);
  127. rcu_read_lock();
  128. dev = rcu_dereference(spriv->dev);
  129. if (!dev)
  130. goto error_rcu;
  131. priv = netdev_priv(dev);
  132. if (dev_forward_skb(dev, skb) == NET_RX_SUCCESS) {
  133. atomic_long_inc(&priv->rx_packets);
  134. atomic_long_add(data_len, &priv->rx_bytes);
  135. } else {
  136. atomic_long_inc(&priv->rx_errors);
  137. }
  138. rcu_read_unlock();
  139. return;
  140. error_rcu:
  141. rcu_read_unlock();
  142. error:
  143. kfree_skb(skb);
  144. }
  145. static void l2tp_eth_delete(struct l2tp_session *session)
  146. {
  147. struct l2tp_eth_sess *spriv;
  148. struct net_device *dev;
  149. if (session) {
  150. spriv = l2tp_session_priv(session);
  151. rtnl_lock();
  152. dev = rtnl_dereference(spriv->dev);
  153. if (dev) {
  154. unregister_netdevice(dev);
  155. rtnl_unlock();
  156. module_put(THIS_MODULE);
  157. } else {
  158. rtnl_unlock();
  159. }
  160. }
  161. }
  162. static void l2tp_eth_show(struct seq_file *m, void *arg)
  163. {
  164. struct l2tp_session *session = arg;
  165. struct l2tp_eth_sess *spriv = l2tp_session_priv(session);
  166. struct net_device *dev;
  167. rcu_read_lock();
  168. dev = rcu_dereference(spriv->dev);
  169. if (!dev) {
  170. rcu_read_unlock();
  171. return;
  172. }
  173. dev_hold(dev);
  174. rcu_read_unlock();
  175. seq_printf(m, " interface %s\n", dev->name);
  176. dev_put(dev);
  177. }
  178. static void l2tp_eth_adjust_mtu(struct l2tp_tunnel *tunnel,
  179. struct l2tp_session *session,
  180. struct net_device *dev)
  181. {
  182. unsigned int overhead = 0;
  183. u32 l3_overhead = 0;
  184. u32 mtu;
  185. /* if the encap is UDP, account for UDP header size */
  186. if (tunnel->encap == L2TP_ENCAPTYPE_UDP) {
  187. overhead += sizeof(struct udphdr);
  188. dev->needed_headroom += sizeof(struct udphdr);
  189. }
  190. lock_sock(tunnel->sock);
  191. l3_overhead = kernel_sock_ip_overhead(tunnel->sock);
  192. release_sock(tunnel->sock);
  193. if (l3_overhead == 0) {
  194. /* L3 Overhead couldn't be identified, this could be
  195. * because tunnel->sock was NULL or the socket's
  196. * address family was not IPv4 or IPv6,
  197. * dev mtu stays at 1500.
  198. */
  199. return;
  200. }
  201. /* Adjust MTU, factor overhead - underlay L3, overlay L2 hdr
  202. * UDP overhead, if any, was already factored in above.
  203. */
  204. overhead += session->hdr_len + ETH_HLEN + l3_overhead;
  205. mtu = l2tp_tunnel_dst_mtu(tunnel) - overhead;
  206. if (mtu < dev->min_mtu || mtu > dev->max_mtu)
  207. dev->mtu = ETH_DATA_LEN - overhead;
  208. else
  209. dev->mtu = mtu;
  210. dev->needed_headroom += session->hdr_len;
  211. }
  212. static int l2tp_eth_create(struct net *net, struct l2tp_tunnel *tunnel,
  213. u32 session_id, u32 peer_session_id,
  214. struct l2tp_session_cfg *cfg)
  215. {
  216. unsigned char name_assign_type;
  217. struct net_device *dev;
  218. char name[IFNAMSIZ];
  219. struct l2tp_session *session;
  220. struct l2tp_eth *priv;
  221. struct l2tp_eth_sess *spriv;
  222. int rc;
  223. if (cfg->ifname) {
  224. strlcpy(name, cfg->ifname, IFNAMSIZ);
  225. name_assign_type = NET_NAME_USER;
  226. } else {
  227. strcpy(name, L2TP_ETH_DEV_NAME);
  228. name_assign_type = NET_NAME_ENUM;
  229. }
  230. session = l2tp_session_create(sizeof(*spriv), tunnel, session_id,
  231. peer_session_id, cfg);
  232. if (IS_ERR(session)) {
  233. rc = PTR_ERR(session);
  234. goto err;
  235. }
  236. dev = alloc_netdev(sizeof(*priv), name, name_assign_type,
  237. l2tp_eth_dev_setup);
  238. if (!dev) {
  239. rc = -ENOMEM;
  240. goto err_sess;
  241. }
  242. dev_net_set(dev, net);
  243. dev->min_mtu = 0;
  244. dev->max_mtu = ETH_MAX_MTU;
  245. l2tp_eth_adjust_mtu(tunnel, session, dev);
  246. priv = netdev_priv(dev);
  247. priv->session = session;
  248. session->recv_skb = l2tp_eth_dev_recv;
  249. session->session_close = l2tp_eth_delete;
  250. if (IS_ENABLED(CONFIG_L2TP_DEBUGFS))
  251. session->show = l2tp_eth_show;
  252. spriv = l2tp_session_priv(session);
  253. l2tp_session_inc_refcount(session);
  254. rtnl_lock();
  255. /* Register both device and session while holding the rtnl lock. This
  256. * ensures that l2tp_eth_delete() will see that there's a device to
  257. * unregister, even if it happened to run before we assign spriv->dev.
  258. */
  259. rc = l2tp_session_register(session, tunnel);
  260. if (rc < 0) {
  261. rtnl_unlock();
  262. goto err_sess_dev;
  263. }
  264. rc = register_netdevice(dev);
  265. if (rc < 0) {
  266. rtnl_unlock();
  267. l2tp_session_delete(session);
  268. l2tp_session_dec_refcount(session);
  269. free_netdev(dev);
  270. return rc;
  271. }
  272. strlcpy(session->ifname, dev->name, IFNAMSIZ);
  273. rcu_assign_pointer(spriv->dev, dev);
  274. rtnl_unlock();
  275. l2tp_session_dec_refcount(session);
  276. __module_get(THIS_MODULE);
  277. return 0;
  278. err_sess_dev:
  279. l2tp_session_dec_refcount(session);
  280. free_netdev(dev);
  281. err_sess:
  282. kfree(session);
  283. err:
  284. return rc;
  285. }
  286. static const struct l2tp_nl_cmd_ops l2tp_eth_nl_cmd_ops = {
  287. .session_create = l2tp_eth_create,
  288. .session_delete = l2tp_session_delete,
  289. };
  290. static int __init l2tp_eth_init(void)
  291. {
  292. int err = 0;
  293. err = l2tp_nl_register_ops(L2TP_PWTYPE_ETH, &l2tp_eth_nl_cmd_ops);
  294. if (err)
  295. goto err;
  296. pr_info("L2TP ethernet pseudowire support (L2TPv3)\n");
  297. return 0;
  298. err:
  299. return err;
  300. }
  301. static void __exit l2tp_eth_exit(void)
  302. {
  303. l2tp_nl_unregister_ops(L2TP_PWTYPE_ETH);
  304. }
  305. module_init(l2tp_eth_init);
  306. module_exit(l2tp_eth_exit);
  307. MODULE_LICENSE("GPL");
  308. MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
  309. MODULE_DESCRIPTION("L2TP ethernet pseudowire driver");
  310. MODULE_VERSION("1.0");
  311. MODULE_ALIAS_L2TP_PWTYPE(5);