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 = atomic_long_read(&priv->tx_bytes); 118 stats->tx_packets = atomic_long_read(&priv->tx_packets); 119 stats->tx_dropped = atomic_long_read(&priv->tx_dropped); 120 stats->rx_bytes = atomic_long_read(&priv->rx_bytes); 121 stats->rx_packets = atomic_long_read(&priv->rx_packets); 122 stats->rx_errors = atomic_long_read(&priv->rx_errors); 123 } 124 125 static const struct net_device_ops l2tp_eth_netdev_ops = { 126 .ndo_init = l2tp_eth_dev_init, 127 .ndo_uninit = l2tp_eth_dev_uninit, 128 .ndo_start_xmit = l2tp_eth_dev_xmit, 129 .ndo_get_stats64 = l2tp_eth_get_stats64, 130 .ndo_set_mac_address = eth_mac_addr, 131 }; 132 133 static struct device_type l2tpeth_type = { 134 .name = "l2tpeth", 135 }; 136 137 static void l2tp_eth_dev_setup(struct net_device *dev) 138 { 139 SET_NETDEV_DEVTYPE(dev, &l2tpeth_type); 140 ether_setup(dev); 141 dev->priv_flags &= ~IFF_TX_SKB_SHARING; 142 dev->features |= NETIF_F_LLTX; 143 dev->netdev_ops = &l2tp_eth_netdev_ops; 144 dev->destructor = free_netdev; 145 } 146 147 static void l2tp_eth_dev_recv(struct l2tp_session *session, struct sk_buff *skb, int data_len) 148 { 149 struct l2tp_eth_sess *spriv = l2tp_session_priv(session); 150 struct net_device *dev = spriv->dev; 151 struct l2tp_eth *priv = netdev_priv(dev); 152 153 if (session->debug & L2TP_MSG_DATA) { 154 unsigned int length; 155 156 length = min(32u, skb->len); 157 if (!pskb_may_pull(skb, length)) 158 goto error; 159 160 pr_debug("%s: eth recv\n", session->name); 161 print_hex_dump_bytes("", DUMP_PREFIX_OFFSET, skb->data, length); 162 } 163 164 if (!pskb_may_pull(skb, ETH_HLEN)) 165 goto error; 166 167 secpath_reset(skb); 168 169 /* checksums verified by L2TP */ 170 skb->ip_summed = CHECKSUM_NONE; 171 172 skb_dst_drop(skb); 173 nf_reset(skb); 174 175 if (dev_forward_skb(dev, skb) == NET_RX_SUCCESS) { 176 atomic_long_inc(&priv->rx_packets); 177 atomic_long_add(data_len, &priv->rx_bytes); 178 } else { 179 atomic_long_inc(&priv->rx_errors); 180 } 181 return; 182 183 error: 184 atomic_long_inc(&priv->rx_errors); 185 kfree_skb(skb); 186 } 187 188 static void l2tp_eth_delete(struct l2tp_session *session) 189 { 190 struct l2tp_eth_sess *spriv; 191 struct net_device *dev; 192 193 if (session) { 194 spriv = l2tp_session_priv(session); 195 dev = spriv->dev; 196 if (dev) { 197 unregister_netdev(dev); 198 spriv->dev = NULL; 199 module_put(THIS_MODULE); 200 } 201 } 202 } 203 204 #if IS_ENABLED(CONFIG_L2TP_DEBUGFS) 205 static void l2tp_eth_show(struct seq_file *m, void *arg) 206 { 207 struct l2tp_session *session = arg; 208 struct l2tp_eth_sess *spriv = l2tp_session_priv(session); 209 struct net_device *dev = spriv->dev; 210 211 seq_printf(m, " interface %s\n", dev->name); 212 } 213 #endif 214 215 static void l2tp_eth_adjust_mtu(struct l2tp_tunnel *tunnel, 216 struct l2tp_session *session, 217 struct net_device *dev) 218 { 219 unsigned int overhead = 0; 220 struct dst_entry *dst; 221 u32 l3_overhead = 0; 222 223 /* if the encap is UDP, account for UDP header size */ 224 if (tunnel->encap == L2TP_ENCAPTYPE_UDP) { 225 overhead += sizeof(struct udphdr); 226 dev->needed_headroom += sizeof(struct udphdr); 227 } 228 if (session->mtu != 0) { 229 dev->mtu = session->mtu; 230 dev->needed_headroom += session->hdr_len; 231 return; 232 } 233 lock_sock(tunnel->sock); 234 l3_overhead = kernel_sock_ip_overhead(tunnel->sock); 235 release_sock(tunnel->sock); 236 if (l3_overhead == 0) { 237 /* L3 Overhead couldn't be identified, this could be 238 * because tunnel->sock was NULL or the socket's 239 * address family was not IPv4 or IPv6, 240 * dev mtu stays at 1500. 241 */ 242 return; 243 } 244 /* Adjust MTU, factor overhead - underlay L3, overlay L2 hdr 245 * UDP overhead, if any, was already factored in above. 246 */ 247 overhead += session->hdr_len + ETH_HLEN + l3_overhead; 248 249 /* If PMTU discovery was enabled, use discovered MTU on L2TP device */ 250 dst = sk_dst_get(tunnel->sock); 251 if (dst) { 252 /* dst_mtu will use PMTU if found, else fallback to intf MTU */ 253 u32 pmtu = dst_mtu(dst); 254 255 if (pmtu != 0) 256 dev->mtu = pmtu; 257 dst_release(dst); 258 } 259 session->mtu = dev->mtu - overhead; 260 dev->mtu = session->mtu; 261 dev->needed_headroom += session->hdr_len; 262 } 263 264 static int l2tp_eth_create(struct net *net, u32 tunnel_id, u32 session_id, u32 peer_session_id, struct l2tp_session_cfg *cfg) 265 { 266 unsigned char name_assign_type; 267 struct net_device *dev; 268 char name[IFNAMSIZ]; 269 struct l2tp_tunnel *tunnel; 270 struct l2tp_session *session; 271 struct l2tp_eth *priv; 272 struct l2tp_eth_sess *spriv; 273 int rc; 274 struct l2tp_eth_net *pn; 275 276 tunnel = l2tp_tunnel_find(net, tunnel_id); 277 if (!tunnel) { 278 rc = -ENODEV; 279 goto out; 280 } 281 282 if (cfg->ifname) { 283 strlcpy(name, cfg->ifname, IFNAMSIZ); 284 name_assign_type = NET_NAME_USER; 285 } else { 286 strcpy(name, L2TP_ETH_DEV_NAME); 287 name_assign_type = NET_NAME_ENUM; 288 } 289 290 session = l2tp_session_create(sizeof(*spriv), tunnel, session_id, 291 peer_session_id, cfg); 292 if (IS_ERR(session)) { 293 rc = PTR_ERR(session); 294 goto out; 295 } 296 297 dev = alloc_netdev(sizeof(*priv), name, name_assign_type, 298 l2tp_eth_dev_setup); 299 if (!dev) { 300 rc = -ENOMEM; 301 goto out_del_session; 302 } 303 304 dev_net_set(dev, net); 305 dev->min_mtu = 0; 306 dev->max_mtu = ETH_MAX_MTU; 307 l2tp_eth_adjust_mtu(tunnel, session, dev); 308 309 priv = netdev_priv(dev); 310 priv->dev = dev; 311 priv->session = session; 312 INIT_LIST_HEAD(&priv->list); 313 314 priv->tunnel_sock = tunnel->sock; 315 session->recv_skb = l2tp_eth_dev_recv; 316 session->session_close = l2tp_eth_delete; 317 #if IS_ENABLED(CONFIG_L2TP_DEBUGFS) 318 session->show = l2tp_eth_show; 319 #endif 320 321 spriv = l2tp_session_priv(session); 322 spriv->dev = dev; 323 324 rc = register_netdev(dev); 325 if (rc < 0) 326 goto out_del_dev; 327 328 __module_get(THIS_MODULE); 329 /* Must be done after register_netdev() */ 330 strlcpy(session->ifname, dev->name, IFNAMSIZ); 331 332 dev_hold(dev); 333 pn = l2tp_eth_pernet(dev_net(dev)); 334 spin_lock(&pn->l2tp_eth_lock); 335 list_add(&priv->list, &pn->l2tp_eth_dev_list); 336 spin_unlock(&pn->l2tp_eth_lock); 337 338 return 0; 339 340 out_del_dev: 341 free_netdev(dev); 342 spriv->dev = NULL; 343 out_del_session: 344 l2tp_session_delete(session); 345 out: 346 return rc; 347 } 348 349 static __net_init int l2tp_eth_init_net(struct net *net) 350 { 351 struct l2tp_eth_net *pn = net_generic(net, l2tp_eth_net_id); 352 353 INIT_LIST_HEAD(&pn->l2tp_eth_dev_list); 354 spin_lock_init(&pn->l2tp_eth_lock); 355 356 return 0; 357 } 358 359 static struct pernet_operations l2tp_eth_net_ops = { 360 .init = l2tp_eth_init_net, 361 .id = &l2tp_eth_net_id, 362 .size = sizeof(struct l2tp_eth_net), 363 }; 364 365 366 static const struct l2tp_nl_cmd_ops l2tp_eth_nl_cmd_ops = { 367 .session_create = l2tp_eth_create, 368 .session_delete = l2tp_session_delete, 369 }; 370 371 372 static int __init l2tp_eth_init(void) 373 { 374 int err = 0; 375 376 err = l2tp_nl_register_ops(L2TP_PWTYPE_ETH, &l2tp_eth_nl_cmd_ops); 377 if (err) 378 goto out; 379 380 err = register_pernet_device(&l2tp_eth_net_ops); 381 if (err) 382 goto out_unreg; 383 384 pr_info("L2TP ethernet pseudowire support (L2TPv3)\n"); 385 386 return 0; 387 388 out_unreg: 389 l2tp_nl_unregister_ops(L2TP_PWTYPE_ETH); 390 out: 391 return err; 392 } 393 394 static void __exit l2tp_eth_exit(void) 395 { 396 unregister_pernet_device(&l2tp_eth_net_ops); 397 l2tp_nl_unregister_ops(L2TP_PWTYPE_ETH); 398 } 399 400 module_init(l2tp_eth_init); 401 module_exit(l2tp_eth_exit); 402 403 MODULE_LICENSE("GPL"); 404 MODULE_AUTHOR("James Chapman <jchapman@katalix.com>"); 405 MODULE_DESCRIPTION("L2TP ethernet pseudowire driver"); 406 MODULE_VERSION("1.0"); 407 MODULE_ALIAS_L2TP_PWTYPE(5); 408