net/l2tp/l2tp_eth.c

   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
  34 #include "l2tp_core.h"
  35
  36 /* Default device name. May be overridden by name specified by user */
  37 #define L2TP_ETH_DEV_NAME       "l2tpeth%d"
  38
  39 /* via netdev_priv() */
  40 struct l2tp_eth {
  41         struct net_device       *dev;
  42         struct sock             *tunnel_sock;
  43         struct l2tp_session     *session;
  44         struct list_head        list;
  45         atomic_long_t           tx_bytes;
  46         atomic_long_t           tx_packets;
  47         atomic_long_t           tx_dropped;
  48         atomic_long_t           rx_bytes;
  49         atomic_long_t           rx_packets;
  50         atomic_long_t           rx_errors;
  51 };
  52
  53 /* via l2tp_session_priv() */
  54 struct l2tp_eth_sess {
  55         struct net_device       *dev;
  56 };
  57
  58 /* per-net private data for this module */
  59 static unsigned int l2tp_eth_net_id;
  60 struct l2tp_eth_net {
  61         struct list_head l2tp_eth_dev_list;
  62         spinlock_t l2tp_eth_lock;
  63 };
  64
  65 static inline struct l2tp_eth_net *l2tp_eth_pernet(struct net *net)
  66 {
  67         return net_generic(net, l2tp_eth_net_id);
  68 }
  69
  70 static int l2tp_eth_dev_init(struct net_device *dev)
  71 {
  72         struct l2tp_eth *priv = netdev_priv(dev);
  73
  74         priv->dev = dev;
  75         eth_hw_addr_random(dev);
  76         eth_broadcast_addr(dev->broadcast);
  77         netdev_lockdep_set_classes(dev);
  78
  79         return 0;
  80 }
  81
  82 static void l2tp_eth_dev_uninit(struct net_device *dev)
  83 {
  84         struct l2tp_eth *priv = netdev_priv(dev);
  85         struct l2tp_eth_net *pn = l2tp_eth_pernet(dev_net(dev));
  86
  87         spin_lock(&pn->l2tp_eth_lock);
  88         list_del_init(&priv->list);
  89         spin_unlock(&pn->l2tp_eth_lock);
  90         dev_put(dev);
  91 }
  92
  93 static int l2tp_eth_dev_xmit(struct sk_buff *skb, struct net_device *dev)
  94 {
  95         struct l2tp_eth *priv = netdev_priv(dev);
  96         struct l2tp_session *session = priv->session;
  97         unsigned int len = skb->len;
  98         int ret = l2tp_xmit_skb(session, skb, session->hdr_len);
  99
 100         if (likely(ret == NET_XMIT_SUCCESS)) {
 101                 atomic_long_add(len, &priv->tx_bytes);
 102                 atomic_long_inc(&priv->tx_packets);
 103         } else {
 104                 atomic_long_inc(&priv->tx_dropped);
 105         }
 106         return NETDEV_TX_OK;
 107 }
 108
 109 static void l2tp_eth_get_stats64(struct net_device *dev,
 110                                  struct rtnl_link_stats64 *stats)
 111 {
 112         struct l2tp_eth *priv = netdev_priv(dev);
 113
 114         stats->tx_bytes   = atomic_long_read(&priv->tx_bytes);
 115         stats->tx_packets = atomic_long_read(&priv->tx_packets);
 116         stats->tx_dropped = atomic_long_read(&priv->tx_dropped);
 117         stats->rx_bytes   = atomic_long_read(&priv->rx_bytes);
 118         stats->rx_packets = atomic_long_read(&priv->rx_packets);
 119         stats->rx_errors  = atomic_long_read(&priv->rx_errors);
 120 }
 121
 122 static const struct net_device_ops l2tp_eth_netdev_ops = {
 123         .ndo_init               = l2tp_eth_dev_init,
 124         .ndo_uninit             = l2tp_eth_dev_uninit,
 125         .ndo_start_xmit         = l2tp_eth_dev_xmit,
 126         .ndo_get_stats64        = l2tp_eth_get_stats64,
 127         .ndo_set_mac_address    = eth_mac_addr,
 128 };
 129
 130 static void l2tp_eth_dev_setup(struct net_device *dev)
 131 {
 132         ether_setup(dev);
 133         dev->priv_flags         &= ~IFF_TX_SKB_SHARING;
 134         dev->features           |= NETIF_F_LLTX;
 135         dev->netdev_ops         = &l2tp_eth_netdev_ops;
 136         dev->destructor         = free_netdev;
 137 }
 138
 139 static void l2tp_eth_dev_recv(struct l2tp_session *session, struct sk_buff *skb, int data_len)
 140 {
 141         struct l2tp_eth_sess *spriv = l2tp_session_priv(session);
 142         struct net_device *dev = spriv->dev;
 143         struct l2tp_eth *priv = netdev_priv(dev);
 144
 145         if (session->debug & L2TP_MSG_DATA) {
 146                 unsigned int length;
 147
 148                 length = min(32u, skb->len);
 149                 if (!pskb_may_pull(skb, length))
 150                         goto error;
 151
 152                 pr_debug("%s: eth recv\n", session->name);
 153                 print_hex_dump_bytes("", DUMP_PREFIX_OFFSET, skb->data, length);
 154         }
 155
 156         if (!pskb_may_pull(skb, ETH_HLEN))
 157                 goto error;
 158
 159         secpath_reset(skb);
 160
 161         /* checksums verified by L2TP */
 162         skb->ip_summed = CHECKSUM_NONE;
 163
 164         skb_dst_drop(skb);
 165         nf_reset(skb);
 166
 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);
 170         } else {
 171                 atomic_long_inc(&priv->rx_errors);
 172         }
 173         return;
 174
 175 error:
 176         atomic_long_inc(&priv->rx_errors);
 177         kfree_skb(skb);
 178 }
 179
 180 static void l2tp_eth_delete(struct l2tp_session *session)
 181 {
 182         struct l2tp_eth_sess *spriv;
 183         struct net_device *dev;
 184
 185         if (session) {
 186                 spriv = l2tp_session_priv(session);
 187                 dev = spriv->dev;
 188                 if (dev) {
 189                         unregister_netdev(dev);
 190                         spriv->dev = NULL;
 191                         module_put(THIS_MODULE);
 192                 }
 193         }
 194 }
 195
 196 #if IS_ENABLED(CONFIG_L2TP_DEBUGFS)
 197 static void l2tp_eth_show(struct seq_file *m, void *arg)
 198 {
 199         struct l2tp_session *session = arg;
 200         struct l2tp_eth_sess *spriv = l2tp_session_priv(session);
 201         struct net_device *dev = spriv->dev;
 202
 203         seq_printf(m, "   interface %s\n", dev->name);
 204 }
 205 #endif
 206
 207 static int l2tp_eth_create(struct net *net, u32 tunnel_id, u32 session_id, u32 peer_session_id, struct l2tp_session_cfg *cfg)
 208 {
 209         struct net_device *dev;
 210         char name[IFNAMSIZ];
 211         struct l2tp_tunnel *tunnel;
 212         struct l2tp_session *session;
 213         struct l2tp_eth *priv;
 214         struct l2tp_eth_sess *spriv;
 215         int rc;
 216         struct l2tp_eth_net *pn;
 217
 218         tunnel = l2tp_tunnel_find(net, tunnel_id);
 219         if (!tunnel) {
 220                 rc = -ENODEV;
 221                 goto out;
 222         }
 223
 224         session = l2tp_session_find(net, tunnel, session_id);
 225         if (session) {
 226                 rc = -EEXIST;
 227                 goto out;
 228         }
 229
 230         if (cfg->ifname) {
 231                 dev = dev_get_by_name(net, cfg->ifname);
 232                 if (dev) {
 233                         dev_put(dev);
 234                         rc = -EEXIST;
 235                         goto out;
 236                 }
 237                 strlcpy(name, cfg->ifname, IFNAMSIZ);
 238         } else
 239                 strcpy(name, L2TP_ETH_DEV_NAME);
 240
 241         session = l2tp_session_create(sizeof(*spriv), tunnel, session_id,
 242                                       peer_session_id, cfg);
 243         if (!session) {
 244                 rc = -ENOMEM;
 245                 goto out;
 246         }
 247
 248         dev = alloc_netdev(sizeof(*priv), name, NET_NAME_UNKNOWN,
 249                            l2tp_eth_dev_setup);
 250         if (!dev) {
 251                 rc = -ENOMEM;
 252                 goto out_del_session;
 253         }
 254
 255         dev_net_set(dev, net);
 256         if (session->mtu == 0)
 257                 session->mtu = dev->mtu - session->hdr_len;
 258         dev->mtu = session->mtu;
 259         dev->needed_headroom += session->hdr_len;
 260         dev->min_mtu = 0;
 261         dev->max_mtu = ETH_MAX_MTU;
 262
 263         priv = netdev_priv(dev);
 264         priv->dev = dev;
 265         priv->session = session;
 266         INIT_LIST_HEAD(&priv->list);
 267
 268         priv->tunnel_sock = tunnel->sock;
 269         session->recv_skb = l2tp_eth_dev_recv;
 270         session->session_close = l2tp_eth_delete;
 271 #if IS_ENABLED(CONFIG_L2TP_DEBUGFS)
 272         session->show = l2tp_eth_show;
 273 #endif
 274
 275         spriv = l2tp_session_priv(session);
 276         spriv->dev = dev;
 277
 278         rc = register_netdev(dev);
 279         if (rc < 0)
 280                 goto out_del_dev;
 281
 282         __module_get(THIS_MODULE);
 283         /* Must be done after register_netdev() */
 284         strlcpy(session->ifname, dev->name, IFNAMSIZ);
 285
 286         dev_hold(dev);
 287         pn = l2tp_eth_pernet(dev_net(dev));
 288         spin_lock(&pn->l2tp_eth_lock);
 289         list_add(&priv->list, &pn->l2tp_eth_dev_list);
 290         spin_unlock(&pn->l2tp_eth_lock);
 291
 292         return 0;
 293
 294 out_del_dev:
 295         free_netdev(dev);
 296         spriv->dev = NULL;
 297 out_del_session:
 298         l2tp_session_delete(session);
 299 out:
 300         return rc;
 301 }
 302
 303 static __net_init int l2tp_eth_init_net(struct net *net)
 304 {
 305         struct l2tp_eth_net *pn = net_generic(net, l2tp_eth_net_id);
 306
 307         INIT_LIST_HEAD(&pn->l2tp_eth_dev_list);
 308         spin_lock_init(&pn->l2tp_eth_lock);
 309
 310         return 0;
 311 }
 312
 313 static struct pernet_operations l2tp_eth_net_ops = {
 314         .init = l2tp_eth_init_net,
 315         .id   = &l2tp_eth_net_id,
 316         .size = sizeof(struct l2tp_eth_net),
 317 };
 318
 319
 320 static const struct l2tp_nl_cmd_ops l2tp_eth_nl_cmd_ops = {
 321         .session_create = l2tp_eth_create,
 322         .session_delete = l2tp_session_delete,
 323 };
 324
 325
 326 static int __init l2tp_eth_init(void)
 327 {
 328         int err = 0;
 329
 330         err = l2tp_nl_register_ops(L2TP_PWTYPE_ETH, &l2tp_eth_nl_cmd_ops);
 331         if (err)
 332                 goto out;
 333
 334         err = register_pernet_device(&l2tp_eth_net_ops);
 335         if (err)
 336                 goto out_unreg;
 337
 338         pr_info("L2TP ethernet pseudowire support (L2TPv3)\n");
 339
 340         return 0;
 341
 342 out_unreg:
 343         l2tp_nl_unregister_ops(L2TP_PWTYPE_ETH);
 344 out:
 345         return err;
 346 }
 347
 348 static void __exit l2tp_eth_exit(void)
 349 {
 350         unregister_pernet_device(&l2tp_eth_net_ops);
 351         l2tp_nl_unregister_ops(L2TP_PWTYPE_ETH);
 352 }
 353
 354 module_init(l2tp_eth_init);
 355 module_exit(l2tp_eth_exit);
 356
 357 MODULE_LICENSE("GPL");
 358 MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
 359 MODULE_DESCRIPTION("L2TP ethernet pseudowire driver");
 360 MODULE_VERSION("1.0");
 361 MODULE_ALIAS_L2TP_PWTYPE(5);