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 struct lock_class_key l2tp_eth_tx_busylock;
  71 static struct lock_class_key l2tp_qdisc_running_key;
  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         dev->qdisc_tx_busylock = &l2tp_eth_tx_busylock;
  81         dev->qdisc_running_key = &l2tp_qdisc_running_key;
  82
  83         return 0;
  84 }
  85
  86 static void l2tp_eth_dev_uninit(struct net_device *dev)
  87 {
  88         struct l2tp_eth *priv = netdev_priv(dev);
  89         struct l2tp_eth_net *pn = l2tp_eth_pernet(dev_net(dev));
  90
  91         spin_lock(&pn->l2tp_eth_lock);
  92         list_del_init(&priv->list);
  93         spin_unlock(&pn->l2tp_eth_lock);
  94         dev_put(dev);
  95 }
  96
  97 static int l2tp_eth_dev_xmit(struct sk_buff *skb, struct net_device *dev)
  98 {
  99         struct l2tp_eth *priv = netdev_priv(dev);
 100         struct l2tp_session *session = priv->session;
 101         unsigned int len = skb->len;
 102         int ret = l2tp_xmit_skb(session, skb, session->hdr_len);
 103
 104         if (likely(ret == NET_XMIT_SUCCESS)) {
 105                 atomic_long_add(len, &priv->tx_bytes);
 106                 atomic_long_inc(&priv->tx_packets);
 107         } else {
 108                 atomic_long_inc(&priv->tx_dropped);
 109         }
 110         return NETDEV_TX_OK;
 111 }
 112
 113 static struct rtnl_link_stats64 *l2tp_eth_get_stats64(struct net_device *dev,
 114                                                       struct rtnl_link_stats64 *stats)
 115 {
 116         struct l2tp_eth *priv = netdev_priv(dev);
 117
 118         stats->tx_bytes   = atomic_long_read(&priv->tx_bytes);
 119         stats->tx_packets = atomic_long_read(&priv->tx_packets);
 120         stats->tx_dropped = atomic_long_read(&priv->tx_dropped);
 121         stats->rx_bytes   = atomic_long_read(&priv->rx_bytes);
 122         stats->rx_packets = atomic_long_read(&priv->rx_packets);
 123         stats->rx_errors  = atomic_long_read(&priv->rx_errors);
 124         return stats;
 125 }
 126
 127
 128 static struct net_device_ops l2tp_eth_netdev_ops = {
 129         .ndo_init               = l2tp_eth_dev_init,
 130         .ndo_uninit             = l2tp_eth_dev_uninit,
 131         .ndo_start_xmit         = l2tp_eth_dev_xmit,
 132         .ndo_get_stats64        = l2tp_eth_get_stats64,
 133         .ndo_set_mac_address    = eth_mac_addr,
 134 };
 135
 136 static void l2tp_eth_dev_setup(struct net_device *dev)
 137 {
 138         ether_setup(dev);
 139         dev->priv_flags         &= ~IFF_TX_SKB_SHARING;
 140         dev->features           |= NETIF_F_LLTX;
 141         dev->netdev_ops         = &l2tp_eth_netdev_ops;
 142         dev->destructor         = free_netdev;
 143 }
 144
 145 static void l2tp_eth_dev_recv(struct l2tp_session *session, struct sk_buff *skb, int data_len)
 146 {
 147         struct l2tp_eth_sess *spriv = l2tp_session_priv(session);
 148         struct net_device *dev = spriv->dev;
 149         struct l2tp_eth *priv = netdev_priv(dev);
 150
 151         if (session->debug & L2TP_MSG_DATA) {
 152                 unsigned int length;
 153
 154                 length = min(32u, skb->len);
 155                 if (!pskb_may_pull(skb, length))
 156                         goto error;
 157
 158                 pr_debug("%s: eth recv\n", session->name);
 159                 print_hex_dump_bytes("", DUMP_PREFIX_OFFSET, skb->data, length);
 160         }
 161
 162         if (!pskb_may_pull(skb, ETH_HLEN))
 163                 goto error;
 164
 165         secpath_reset(skb);
 166
 167         /* checksums verified by L2TP */
 168         skb->ip_summed = CHECKSUM_NONE;
 169
 170         skb_dst_drop(skb);
 171         nf_reset(skb);
 172
 173         if (dev_forward_skb(dev, skb) == NET_RX_SUCCESS) {
 174                 atomic_long_inc(&priv->rx_packets);
 175                 atomic_long_add(data_len, &priv->rx_bytes);
 176         } else {
 177                 atomic_long_inc(&priv->rx_errors);
 178         }
 179         return;
 180
 181 error:
 182         atomic_long_inc(&priv->rx_errors);
 183         kfree_skb(skb);
 184 }
 185
 186 static void l2tp_eth_delete(struct l2tp_session *session)
 187 {
 188         struct l2tp_eth_sess *spriv;
 189         struct net_device *dev;
 190
 191         if (session) {
 192                 spriv = l2tp_session_priv(session);
 193                 dev = spriv->dev;
 194                 if (dev) {
 195                         unregister_netdev(dev);
 196                         spriv->dev = NULL;
 197                         module_put(THIS_MODULE);
 198                 }
 199         }
 200 }
 201
 202 #if defined(CONFIG_L2TP_DEBUGFS) || defined(CONFIG_L2TP_DEBUGFS_MODULE)
 203 static void l2tp_eth_show(struct seq_file *m, void *arg)
 204 {
 205         struct l2tp_session *session = arg;
 206         struct l2tp_eth_sess *spriv = l2tp_session_priv(session);
 207         struct net_device *dev = spriv->dev;
 208
 209         seq_printf(m, "   interface %s\n", dev->name);
 210 }
 211 #endif
 212
 213 static int l2tp_eth_create(struct net *net, u32 tunnel_id, u32 session_id, u32 peer_session_id, struct l2tp_session_cfg *cfg)
 214 {
 215         struct net_device *dev;
 216         char name[IFNAMSIZ];
 217         struct l2tp_tunnel *tunnel;
 218         struct l2tp_session *session;
 219         struct l2tp_eth *priv;
 220         struct l2tp_eth_sess *spriv;
 221         int rc;
 222         struct l2tp_eth_net *pn;
 223
 224         tunnel = l2tp_tunnel_find(net, tunnel_id);
 225         if (!tunnel) {
 226                 rc = -ENODEV;
 227                 goto out;
 228         }
 229
 230         session = l2tp_session_find(net, tunnel, session_id);
 231         if (session) {
 232                 rc = -EEXIST;
 233                 goto out;
 234         }
 235
 236         if (cfg->ifname) {
 237                 dev = dev_get_by_name(net, cfg->ifname);
 238                 if (dev) {
 239                         dev_put(dev);
 240                         rc = -EEXIST;
 241                         goto out;
 242                 }
 243                 strlcpy(name, cfg->ifname, IFNAMSIZ);
 244         } else
 245                 strcpy(name, L2TP_ETH_DEV_NAME);
 246
 247         session = l2tp_session_create(sizeof(*spriv), tunnel, session_id,
 248                                       peer_session_id, cfg);
 249         if (!session) {
 250                 rc = -ENOMEM;
 251                 goto out;
 252         }
 253
 254         dev = alloc_netdev(sizeof(*priv), name, NET_NAME_UNKNOWN,
 255                            l2tp_eth_dev_setup);
 256         if (!dev) {
 257                 rc = -ENOMEM;
 258                 goto out_del_session;
 259         }
 260
 261         dev_net_set(dev, net);
 262         if (session->mtu == 0)
 263                 session->mtu = dev->mtu - session->hdr_len;
 264         dev->mtu = session->mtu;
 265         dev->needed_headroom += session->hdr_len;
 266
 267         priv = netdev_priv(dev);
 268         priv->dev = dev;
 269         priv->session = session;
 270         INIT_LIST_HEAD(&priv->list);
 271
 272         priv->tunnel_sock = tunnel->sock;
 273         session->recv_skb = l2tp_eth_dev_recv;
 274         session->session_close = l2tp_eth_delete;
 275 #if defined(CONFIG_L2TP_DEBUGFS) || defined(CONFIG_L2TP_DEBUGFS_MODULE)
 276         session->show = l2tp_eth_show;
 277 #endif
 278
 279         spriv = l2tp_session_priv(session);
 280         spriv->dev = dev;
 281
 282         rc = register_netdev(dev);
 283         if (rc < 0)
 284                 goto out_del_dev;
 285
 286         __module_get(THIS_MODULE);
 287         /* Must be done after register_netdev() */
 288         strlcpy(session->ifname, dev->name, IFNAMSIZ);
 289
 290         dev_hold(dev);
 291         pn = l2tp_eth_pernet(dev_net(dev));
 292         spin_lock(&pn->l2tp_eth_lock);
 293         list_add(&priv->list, &pn->l2tp_eth_dev_list);
 294         spin_unlock(&pn->l2tp_eth_lock);
 295
 296         return 0;
 297
 298 out_del_dev:
 299         free_netdev(dev);
 300         spriv->dev = NULL;
 301 out_del_session:
 302         l2tp_session_delete(session);
 303 out:
 304         return rc;
 305 }
 306
 307 static __net_init int l2tp_eth_init_net(struct net *net)
 308 {
 309         struct l2tp_eth_net *pn = net_generic(net, l2tp_eth_net_id);
 310
 311         INIT_LIST_HEAD(&pn->l2tp_eth_dev_list);
 312         spin_lock_init(&pn->l2tp_eth_lock);
 313
 314         return 0;
 315 }
 316
 317 static struct pernet_operations l2tp_eth_net_ops = {
 318         .init = l2tp_eth_init_net,
 319         .id   = &l2tp_eth_net_id,
 320         .size = sizeof(struct l2tp_eth_net),
 321 };
 322
 323
 324 static const struct l2tp_nl_cmd_ops l2tp_eth_nl_cmd_ops = {
 325         .session_create = l2tp_eth_create,
 326         .session_delete = l2tp_session_delete,
 327 };
 328
 329
 330 static int __init l2tp_eth_init(void)
 331 {
 332         int err = 0;
 333
 334         err = l2tp_nl_register_ops(L2TP_PWTYPE_ETH, &l2tp_eth_nl_cmd_ops);
 335         if (err)
 336                 goto out;
 337
 338         err = register_pernet_device(&l2tp_eth_net_ops);
 339         if (err)
 340                 goto out_unreg;
 341
 342         pr_info("L2TP ethernet pseudowire support (L2TPv3)\n");
 343
 344         return 0;
 345
 346 out_unreg:
 347         l2tp_nl_unregister_ops(L2TP_PWTYPE_ETH);
 348 out:
 349         return err;
 350 }
 351
 352 static void __exit l2tp_eth_exit(void)
 353 {
 354         unregister_pernet_device(&l2tp_eth_net_ops);
 355         l2tp_nl_unregister_ops(L2TP_PWTYPE_ETH);
 356 }
 357
 358 module_init(l2tp_eth_init);
 359 module_exit(l2tp_eth_exit);
 360
 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);