1 /* 2 * L2TPv3 ethernet pseudowire driver 3 * 4 * Copyright (c) 2008,2009,2010 Katalix Systems Ltd 5 * 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. 10 */ 11 12 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 13 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> 19 #include <linux/in.h> 20 #include <linux/etherdevice.h> 21 #include <linux/spinlock.h> 22 #include <net/sock.h> 23 #include <net/ip.h> 24 #include <net/icmp.h> 25 #include <net/udp.h> 26 #include <net/inet_common.h> 27 #include <net/inet_hashtables.h> 28 #include <net/tcp_states.h> 29 #include <net/protocol.h> 30 #include <net/xfrm.h> 31 #include <net/net_namespace.h> 32 #include <net/netns/generic.h> 33 #include <linux/ip.h> 34 #include <linux/ipv6.h> 35 #include <linux/udp.h> 36 37 #include "l2tp_core.h" 38 39 /* Default device name. May be overridden by name specified by user */ 40 #define L2TP_ETH_DEV_NAME "l2tpeth%d" 41 42 /* via netdev_priv() */ 43 struct l2tp_eth { 44 struct net_device *dev; 45 struct sock *tunnel_sock; 46 struct l2tp_session *session; 47 struct list_head list; 48 atomic_long_t tx_bytes; 49 atomic_long_t tx_packets; 50 atomic_long_t tx_dropped; 51 atomic_long_t rx_bytes; 52 atomic_long_t rx_packets; 53 atomic_long_t rx_errors; 54 }; 55 56 /* via l2tp_session_priv() */ 57 struct l2tp_eth_sess { 58 struct net_device *dev; 59 }; 60 61 /* per-net private data for this module */ 62 static unsigned int l2tp_eth_net_id; 63 struct l2tp_eth_net { 64 struct list_head l2tp_eth_dev_list; 65 spinlock_t l2tp_eth_lock; 66 }; 67 68 static inline struct l2tp_eth_net *l2tp_eth_pernet(struct net *net) 69 { 70 return net_generic(net, l2tp_eth_net_id); 71 } 72 73 static int l2tp_eth_dev_init(struct net_device *dev) 74 { 75 struct l2tp_eth *priv = netdev_priv(dev); 76 77 priv->dev = dev; 78 eth_hw_addr_random(dev); 79 eth_broadcast_addr(dev->broadcast); 80 netdev_lockdep_set_classes(dev); 81 82 return 0; 83 } 84 85 static void l2tp_eth_dev_uninit(struct net_device *dev) 86 { 87 struct l2tp_eth *priv = netdev_priv(dev); 88 struct l2tp_eth_net *pn = l2tp_eth_pernet(dev_net(dev)); 89 90 spin_lock(&pn->l2tp_eth_lock); 91 list_del_init(&priv->list); 92 spin_unlock(&pn->l2tp_eth_lock); 93 dev_put(dev); 94 } 95 96 static int l2tp_eth_dev_xmit(struct sk_buff *skb, struct net_device *dev) 97 { 98 struct l2tp_eth *priv = netdev_priv(dev); 99 struct l2tp_session *session = priv->session; 100 unsigned int len = skb->len; 101 int ret = l2tp_xmit_skb(session, skb, session->hdr_len); 102 103 if (likely(ret == NET_XMIT_SUCCESS)) { 104 atomic_long_add(len, &priv->tx_bytes); 105 atomic_long_inc(&priv->tx_packets); 106 } else { 107 atomic_long_inc(&priv->tx_dropped); 108 } 109 return NETDEV_TX_OK; 110 } 111 112 static void l2tp_eth_get_stats64(struct net_device *dev, 113 struct rtnl_link_stats64 *stats) 114 { 115 struct l2tp_eth *priv = netdev_priv(dev); 116 117 stats->tx_bytes = (unsigned long) atomic_long_read(&priv->tx_bytes); 118 stats->tx_packets = (unsigned long) atomic_long_read(&priv->tx_packets); 119 stats->tx_dropped = (unsigned long) atomic_long_read(&priv->tx_dropped); 120 stats->rx_bytes = (unsigned long) atomic_long_read(&priv->rx_bytes); 121 stats->rx_packets = (unsigned long) atomic_long_read(&priv->rx_packets); 122 stats->rx_errors = (unsigned long) atomic_long_read(&priv->rx_errors); 123 124 } 125 126 static const struct net_device_ops l2tp_eth_netdev_ops = { 127 .ndo_init = l2tp_eth_dev_init, 128 .ndo_uninit = l2tp_eth_dev_uninit, 129 .ndo_start_xmit = l2tp_eth_dev_xmit, 130 .ndo_get_stats64 = l2tp_eth_get_stats64, 131 .ndo_set_mac_address = eth_mac_addr, 132 }; 133 134 static struct device_type l2tpeth_type = { 135 .name = "l2tpeth", 136 }; 137 138 static void l2tp_eth_dev_setup(struct net_device *dev) 139 { 140 SET_NETDEV_DEVTYPE(dev, &l2tpeth_type); 141 ether_setup(dev); 142 dev->priv_flags &= ~IFF_TX_SKB_SHARING; 143 dev->features |= NETIF_F_LLTX; 144 dev->netdev_ops = &l2tp_eth_netdev_ops; 145 dev->needs_free_netdev = true; 146 } 147 148 static void l2tp_eth_dev_recv(struct l2tp_session *session, struct sk_buff *skb, int data_len) 149 { 150 struct l2tp_eth_sess *spriv = l2tp_session_priv(session); 151 struct net_device *dev = spriv->dev; 152 struct l2tp_eth *priv = netdev_priv(dev); 153 154 if (session->debug & L2TP_MSG_DATA) { 155 unsigned int length; 156 157 length = min(32u, skb->len); 158 if (!pskb_may_pull(skb, length)) 159 goto error; 160 161 pr_debug("%s: eth recv\n", session->name); 162 print_hex_dump_bytes("", DUMP_PREFIX_OFFSET, skb->data, length); 163 } 164 165 if (!pskb_may_pull(skb, ETH_HLEN)) 166 goto error; 167 168 secpath_reset(skb); 169 170 /* checksums verified by L2TP */ 171 skb->ip_summed = CHECKSUM_NONE; 172 173 skb_dst_drop(skb); 174 nf_reset(skb); 175 176 if (dev_forward_skb(dev, skb) == NET_RX_SUCCESS) { 177 atomic_long_inc(&priv->rx_packets); 178 atomic_long_add(data_len, &priv->rx_bytes); 179 } else { 180 atomic_long_inc(&priv->rx_errors); 181 } 182 return; 183 184 error: 185 atomic_long_inc(&priv->rx_errors); 186 kfree_skb(skb); 187 } 188 189 static void l2tp_eth_delete(struct l2tp_session *session) 190 { 191 struct l2tp_eth_sess *spriv; 192 struct net_device *dev; 193 194 if (session) { 195 spriv = l2tp_session_priv(session); 196 dev = spriv->dev; 197 if (dev) { 198 unregister_netdev(dev); 199 spriv->dev = NULL; 200 module_put(THIS_MODULE); 201 } 202 } 203 } 204 205 #if IS_ENABLED(CONFIG_L2TP_DEBUGFS) 206 static void l2tp_eth_show(struct seq_file *m, void *arg) 207 { 208 struct l2tp_session *session = arg; 209 struct l2tp_eth_sess *spriv = l2tp_session_priv(session); 210 struct net_device *dev = spriv->dev; 211 212 seq_printf(m, " interface %s\n", dev->name); 213 } 214 #endif 215 216 static void l2tp_eth_adjust_mtu(struct l2tp_tunnel *tunnel, 217 struct l2tp_session *session, 218 struct net_device *dev) 219 { 220 unsigned int overhead = 0; 221 struct dst_entry *dst; 222 u32 l3_overhead = 0; 223 224 /* if the encap is UDP, account for UDP header size */ 225 if (tunnel->encap == L2TP_ENCAPTYPE_UDP) { 226 overhead += sizeof(struct udphdr); 227 dev->needed_headroom += sizeof(struct udphdr); 228 } 229 if (session->mtu != 0) { 230 dev->mtu = session->mtu; 231 dev->needed_headroom += session->hdr_len; 232 return; 233 } 234 lock_sock(tunnel->sock); 235 l3_overhead = kernel_sock_ip_overhead(tunnel->sock); 236 release_sock(tunnel->sock); 237 if (l3_overhead == 0) { 238 /* L3 Overhead couldn't be identified, this could be 239 * because tunnel->sock was NULL or the socket's 240 * address family was not IPv4 or IPv6, 241 * dev mtu stays at 1500. 242 */ 243 return; 244 } 245 /* Adjust MTU, factor overhead - underlay L3, overlay L2 hdr 246 * UDP overhead, if any, was already factored in above. 247 */ 248 overhead += session->hdr_len + ETH_HLEN + l3_overhead; 249 250 /* If PMTU discovery was enabled, use discovered MTU on L2TP device */ 251 dst = sk_dst_get(tunnel->sock); 252 if (dst) { 253 /* dst_mtu will use PMTU if found, else fallback to intf MTU */ 254 u32 pmtu = dst_mtu(dst); 255 256 if (pmtu != 0) 257 dev->mtu = pmtu; 258 dst_release(dst); 259 } 260 session->mtu = dev->mtu - overhead; 261 dev->mtu = session->mtu; 262 dev->needed_headroom += session->hdr_len; 263 } 264 265 static int l2tp_eth_create(struct net *net, struct l2tp_tunnel *tunnel, 266 u32 session_id, u32 peer_session_id, 267 struct l2tp_session_cfg *cfg) 268 { 269 unsigned char name_assign_type; 270 struct net_device *dev; 271 char name[IFNAMSIZ]; 272 struct l2tp_session *session; 273 struct l2tp_eth *priv; 274 struct l2tp_eth_sess *spriv; 275 int rc; 276 struct l2tp_eth_net *pn; 277 278 if (cfg->ifname) { 279 strlcpy(name, cfg->ifname, IFNAMSIZ); 280 name_assign_type = NET_NAME_USER; 281 } else { 282 strcpy(name, L2TP_ETH_DEV_NAME); 283 name_assign_type = NET_NAME_ENUM; 284 } 285 286 session = l2tp_session_create(sizeof(*spriv), tunnel, session_id, 287 peer_session_id, cfg); 288 if (IS_ERR(session)) { 289 rc = PTR_ERR(session); 290 goto out; 291 } 292 293 dev = alloc_netdev(sizeof(*priv), name, name_assign_type, 294 l2tp_eth_dev_setup); 295 if (!dev) { 296 rc = -ENOMEM; 297 goto out_del_session; 298 } 299 300 dev_net_set(dev, net); 301 dev->min_mtu = 0; 302 dev->max_mtu = ETH_MAX_MTU; 303 l2tp_eth_adjust_mtu(tunnel, session, dev); 304 305 priv = netdev_priv(dev); 306 priv->dev = dev; 307 priv->session = session; 308 INIT_LIST_HEAD(&priv->list); 309 310 priv->tunnel_sock = tunnel->sock; 311 session->recv_skb = l2tp_eth_dev_recv; 312 session->session_close = l2tp_eth_delete; 313 #if IS_ENABLED(CONFIG_L2TP_DEBUGFS) 314 session->show = l2tp_eth_show; 315 #endif 316 317 spriv = l2tp_session_priv(session); 318 spriv->dev = dev; 319 320 rc = register_netdev(dev); 321 if (rc < 0) 322 goto out_del_dev; 323 324 __module_get(THIS_MODULE); 325 /* Must be done after register_netdev() */ 326 strlcpy(session->ifname, dev->name, IFNAMSIZ); 327 328 dev_hold(dev); 329 pn = l2tp_eth_pernet(dev_net(dev)); 330 spin_lock(&pn->l2tp_eth_lock); 331 list_add(&priv->list, &pn->l2tp_eth_dev_list); 332 spin_unlock(&pn->l2tp_eth_lock); 333 334 return 0; 335 336 out_del_dev: 337 free_netdev(dev); 338 spriv->dev = NULL; 339 out_del_session: 340 l2tp_session_delete(session); 341 out: 342 return rc; 343 } 344 345 static __net_init int l2tp_eth_init_net(struct net *net) 346 { 347 struct l2tp_eth_net *pn = net_generic(net, l2tp_eth_net_id); 348 349 INIT_LIST_HEAD(&pn->l2tp_eth_dev_list); 350 spin_lock_init(&pn->l2tp_eth_lock); 351 352 return 0; 353 } 354 355 static struct pernet_operations l2tp_eth_net_ops = { 356 .init = l2tp_eth_init_net, 357 .id = &l2tp_eth_net_id, 358 .size = sizeof(struct l2tp_eth_net), 359 }; 360 361 362 static const struct l2tp_nl_cmd_ops l2tp_eth_nl_cmd_ops = { 363 .session_create = l2tp_eth_create, 364 .session_delete = l2tp_session_delete, 365 }; 366 367 368 static int __init l2tp_eth_init(void) 369 { 370 int err = 0; 371 372 err = l2tp_nl_register_ops(L2TP_PWTYPE_ETH, &l2tp_eth_nl_cmd_ops); 373 if (err) 374 goto out; 375 376 err = register_pernet_device(&l2tp_eth_net_ops); 377 if (err) 378 goto out_unreg; 379 380 pr_info("L2TP ethernet pseudowire support (L2TPv3)\n"); 381 382 return 0; 383 384 out_unreg: 385 l2tp_nl_unregister_ops(L2TP_PWTYPE_ETH); 386 out: 387 return err; 388 } 389 390 static void __exit l2tp_eth_exit(void) 391 { 392 unregister_pernet_device(&l2tp_eth_net_ops); 393 l2tp_nl_unregister_ops(L2TP_PWTYPE_ETH); 394 } 395 396 module_init(l2tp_eth_init); 397 module_exit(l2tp_eth_exit); 398 399 MODULE_LICENSE("GPL"); 400 MODULE_AUTHOR("James Chapman <jchapman@katalix.com>"); 401 MODULE_DESCRIPTION("L2TP ethernet pseudowire driver"); 402 MODULE_VERSION("1.0"); 403 MODULE_ALIAS_L2TP_PWTYPE(5); 404