linux/net/l2tp/l2tp_eth.c
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   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() */
  40struct 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() */
  54struct l2tp_eth_sess {
  55        struct net_device       *dev;
  56};
  57
  58/* per-net private data for this module */
  59static unsigned int l2tp_eth_net_id;
  60struct l2tp_eth_net {
  61        struct list_head l2tp_eth_dev_list;
  62        spinlock_t l2tp_eth_lock;
  63};
  64
  65static inline struct l2tp_eth_net *l2tp_eth_pernet(struct net *net)
  66{
  67        return net_generic(net, l2tp_eth_net_id);
  68}
  69
  70static struct lock_class_key l2tp_eth_tx_busylock;
  71static int l2tp_eth_dev_init(struct net_device *dev)
  72{
  73        struct l2tp_eth *priv = netdev_priv(dev);
  74
  75        priv->dev = dev;
  76        eth_hw_addr_random(dev);
  77        memset(&dev->broadcast[0], 0xff, 6);
  78        dev->qdisc_tx_busylock = &l2tp_eth_tx_busylock;
  79        return 0;
  80}
  81
  82static 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
  93static 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
 109static struct rtnl_link_stats64 *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        return stats;
 121}
 122
 123
 124static struct net_device_ops l2tp_eth_netdev_ops = {
 125        .ndo_init               = l2tp_eth_dev_init,
 126        .ndo_uninit             = l2tp_eth_dev_uninit,
 127        .ndo_start_xmit         = l2tp_eth_dev_xmit,
 128        .ndo_get_stats64        = l2tp_eth_get_stats64,
 129};
 130
 131static void l2tp_eth_dev_setup(struct net_device *dev)
 132{
 133        ether_setup(dev);
 134        dev->priv_flags         &= ~IFF_TX_SKB_SHARING;
 135        dev->features           |= NETIF_F_LLTX;
 136        dev->netdev_ops         = &l2tp_eth_netdev_ops;
 137        dev->destructor         = free_netdev;
 138}
 139
 140static void l2tp_eth_dev_recv(struct l2tp_session *session, struct sk_buff *skb, int data_len)
 141{
 142        struct l2tp_eth_sess *spriv = l2tp_session_priv(session);
 143        struct net_device *dev = spriv->dev;
 144        struct l2tp_eth *priv = netdev_priv(dev);
 145
 146        if (session->debug & L2TP_MSG_DATA) {
 147                unsigned int length;
 148
 149                length = min(32u, skb->len);
 150                if (!pskb_may_pull(skb, length))
 151                        goto error;
 152
 153                pr_debug("%s: eth recv\n", session->name);
 154                print_hex_dump_bytes("", DUMP_PREFIX_OFFSET, skb->data, length);
 155        }
 156
 157        if (!pskb_may_pull(skb, ETH_HLEN))
 158                goto error;
 159
 160        secpath_reset(skb);
 161
 162        /* checksums verified by L2TP */
 163        skb->ip_summed = CHECKSUM_NONE;
 164
 165        skb_dst_drop(skb);
 166        nf_reset(skb);
 167
 168        if (dev_forward_skb(dev, skb) == NET_RX_SUCCESS) {
 169                atomic_long_inc(&priv->rx_packets);
 170                atomic_long_add(data_len, &priv->rx_bytes);
 171        } else {
 172                atomic_long_inc(&priv->rx_errors);
 173        }
 174        return;
 175
 176error:
 177        atomic_long_inc(&priv->rx_errors);
 178        kfree_skb(skb);
 179}
 180
 181static void l2tp_eth_delete(struct l2tp_session *session)
 182{
 183        struct l2tp_eth_sess *spriv;
 184        struct net_device *dev;
 185
 186        if (session) {
 187                spriv = l2tp_session_priv(session);
 188                dev = spriv->dev;
 189                if (dev) {
 190                        unregister_netdev(dev);
 191                        spriv->dev = NULL;
 192                        module_put(THIS_MODULE);
 193                }
 194        }
 195}
 196
 197#if defined(CONFIG_L2TP_DEBUGFS) || defined(CONFIG_L2TP_DEBUGFS_MODULE)
 198static void l2tp_eth_show(struct seq_file *m, void *arg)
 199{
 200        struct l2tp_session *session = arg;
 201        struct l2tp_eth_sess *spriv = l2tp_session_priv(session);
 202        struct net_device *dev = spriv->dev;
 203
 204        seq_printf(m, "   interface %s\n", dev->name);
 205}
 206#endif
 207
 208static int l2tp_eth_create(struct net *net, u32 tunnel_id, u32 session_id, u32 peer_session_id, struct l2tp_session_cfg *cfg)
 209{
 210        struct net_device *dev;
 211        char name[IFNAMSIZ];
 212        struct l2tp_tunnel *tunnel;
 213        struct l2tp_session *session;
 214        struct l2tp_eth *priv;
 215        struct l2tp_eth_sess *spriv;
 216        int rc;
 217        struct l2tp_eth_net *pn;
 218
 219        tunnel = l2tp_tunnel_find(net, tunnel_id);
 220        if (!tunnel) {
 221                rc = -ENODEV;
 222                goto out;
 223        }
 224
 225        session = l2tp_session_find(net, tunnel, session_id);
 226        if (session) {
 227                rc = -EEXIST;
 228                goto out;
 229        }
 230
 231        if (cfg->ifname) {
 232                dev = dev_get_by_name(net, cfg->ifname);
 233                if (dev) {
 234                        dev_put(dev);
 235                        rc = -EEXIST;
 236                        goto out;
 237                }
 238                strlcpy(name, cfg->ifname, IFNAMSIZ);
 239        } else
 240                strcpy(name, L2TP_ETH_DEV_NAME);
 241
 242        session = l2tp_session_create(sizeof(*spriv), tunnel, session_id,
 243                                      peer_session_id, cfg);
 244        if (!session) {
 245                rc = -ENOMEM;
 246                goto out;
 247        }
 248
 249        dev = alloc_netdev(sizeof(*priv), name, 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
 261        priv = netdev_priv(dev);
 262        priv->dev = dev;
 263        priv->session = session;
 264        INIT_LIST_HEAD(&priv->list);
 265
 266        priv->tunnel_sock = tunnel->sock;
 267        session->recv_skb = l2tp_eth_dev_recv;
 268        session->session_close = l2tp_eth_delete;
 269#if defined(CONFIG_L2TP_DEBUGFS) || defined(CONFIG_L2TP_DEBUGFS_MODULE)
 270        session->show = l2tp_eth_show;
 271#endif
 272
 273        spriv = l2tp_session_priv(session);
 274        spriv->dev = dev;
 275
 276        rc = register_netdev(dev);
 277        if (rc < 0)
 278                goto out_del_dev;
 279
 280        __module_get(THIS_MODULE);
 281        /* Must be done after register_netdev() */
 282        strlcpy(session->ifname, dev->name, IFNAMSIZ);
 283
 284        dev_hold(dev);
 285        pn = l2tp_eth_pernet(dev_net(dev));
 286        spin_lock(&pn->l2tp_eth_lock);
 287        list_add(&priv->list, &pn->l2tp_eth_dev_list);
 288        spin_unlock(&pn->l2tp_eth_lock);
 289
 290        return 0;
 291
 292out_del_dev:
 293        free_netdev(dev);
 294        spriv->dev = NULL;
 295out_del_session:
 296        l2tp_session_delete(session);
 297out:
 298        return rc;
 299}
 300
 301static __net_init int l2tp_eth_init_net(struct net *net)
 302{
 303        struct l2tp_eth_net *pn = net_generic(net, l2tp_eth_net_id);
 304
 305        INIT_LIST_HEAD(&pn->l2tp_eth_dev_list);
 306        spin_lock_init(&pn->l2tp_eth_lock);
 307
 308        return 0;
 309}
 310
 311static struct pernet_operations l2tp_eth_net_ops = {
 312        .init = l2tp_eth_init_net,
 313        .id   = &l2tp_eth_net_id,
 314        .size = sizeof(struct l2tp_eth_net),
 315};
 316
 317
 318static const struct l2tp_nl_cmd_ops l2tp_eth_nl_cmd_ops = {
 319        .session_create = l2tp_eth_create,
 320        .session_delete = l2tp_session_delete,
 321};
 322
 323
 324static int __init l2tp_eth_init(void)
 325{
 326        int err = 0;
 327
 328        err = l2tp_nl_register_ops(L2TP_PWTYPE_ETH, &l2tp_eth_nl_cmd_ops);
 329        if (err)
 330                goto out;
 331
 332        err = register_pernet_device(&l2tp_eth_net_ops);
 333        if (err)
 334                goto out_unreg;
 335
 336        pr_info("L2TP ethernet pseudowire support (L2TPv3)\n");
 337
 338        return 0;
 339
 340out_unreg:
 341        l2tp_nl_unregister_ops(L2TP_PWTYPE_ETH);
 342out:
 343        return err;
 344}
 345
 346static void __exit l2tp_eth_exit(void)
 347{
 348        unregister_pernet_device(&l2tp_eth_net_ops);
 349        l2tp_nl_unregister_ops(L2TP_PWTYPE_ETH);
 350}
 351
 352module_init(l2tp_eth_init);
 353module_exit(l2tp_eth_exit);
 354
 355MODULE_LICENSE("GPL");
 356MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
 357MODULE_DESCRIPTION("L2TP ethernet pseudowire driver");
 358MODULE_VERSION("1.0");
 359
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