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 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        memset(&dev->broadcast[0], 0xff, 6);
  77
  78        return 0;
  79}
  80
  81static void l2tp_eth_dev_uninit(struct net_device *dev)
  82{
  83        struct l2tp_eth *priv = netdev_priv(dev);
  84        struct l2tp_eth_net *pn = l2tp_eth_pernet(dev_net(dev));
  85
  86        spin_lock(&pn->l2tp_eth_lock);
  87        list_del_init(&priv->list);
  88        spin_unlock(&pn->l2tp_eth_lock);
  89        dev_put(dev);
  90}
  91
  92static int l2tp_eth_dev_xmit(struct sk_buff *skb, struct net_device *dev)
  93{
  94        struct l2tp_eth *priv = netdev_priv(dev);
  95        struct l2tp_session *session = priv->session;
  96        unsigned int len = skb->len;
  97        int ret = l2tp_xmit_skb(session, skb, session->hdr_len);
  98
  99        if (likely(ret == NET_XMIT_SUCCESS)) {
 100                atomic_long_add(len, &priv->tx_bytes);
 101                atomic_long_inc(&priv->tx_packets);
 102        } else {
 103                atomic_long_inc(&priv->tx_dropped);
 104        }
 105        return NETDEV_TX_OK;
 106}
 107
 108static struct rtnl_link_stats64 *l2tp_eth_get_stats64(struct net_device *dev,
 109                                                      struct rtnl_link_stats64 *stats)
 110{
 111        struct l2tp_eth *priv = netdev_priv(dev);
 112
 113        stats->tx_bytes   = atomic_long_read(&priv->tx_bytes);
 114        stats->tx_packets = atomic_long_read(&priv->tx_packets);
 115        stats->tx_dropped = atomic_long_read(&priv->tx_dropped);
 116        stats->rx_bytes   = atomic_long_read(&priv->rx_bytes);
 117        stats->rx_packets = atomic_long_read(&priv->rx_packets);
 118        stats->rx_errors  = atomic_long_read(&priv->rx_errors);
 119        return stats;
 120}
 121
 122
 123static struct net_device_ops l2tp_eth_netdev_ops = {
 124        .ndo_init               = l2tp_eth_dev_init,
 125        .ndo_uninit             = l2tp_eth_dev_uninit,
 126        .ndo_start_xmit         = l2tp_eth_dev_xmit,
 127        .ndo_get_stats64        = l2tp_eth_get_stats64,
 128};
 129
 130static 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
 139static 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
 175error:
 176        atomic_long_inc(&priv->rx_errors);
 177        kfree_skb(skb);
 178}
 179
 180static 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 defined(CONFIG_L2TP_DEBUGFS) || defined(CONFIG_L2TP_DEBUGFS_MODULE)
 197static 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
 207static 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, l2tp_eth_dev_setup);
 249        if (!dev) {
 250                rc = -ENOMEM;
 251                goto out_del_session;
 252        }
 253
 254        dev_net_set(dev, net);
 255        if (session->mtu == 0)
 256                session->mtu = dev->mtu - session->hdr_len;
 257        dev->mtu = session->mtu;
 258        dev->needed_headroom += session->hdr_len;
 259
 260        priv = netdev_priv(dev);
 261        priv->dev = dev;
 262        priv->session = session;
 263        INIT_LIST_HEAD(&priv->list);
 264
 265        priv->tunnel_sock = tunnel->sock;
 266        session->recv_skb = l2tp_eth_dev_recv;
 267        session->session_close = l2tp_eth_delete;
 268#if defined(CONFIG_L2TP_DEBUGFS) || defined(CONFIG_L2TP_DEBUGFS_MODULE)
 269        session->show = l2tp_eth_show;
 270#endif
 271
 272        spriv = l2tp_session_priv(session);
 273        spriv->dev = dev;
 274
 275        rc = register_netdev(dev);
 276        if (rc < 0)
 277                goto out_del_dev;
 278
 279        __module_get(THIS_MODULE);
 280        /* Must be done after register_netdev() */
 281        strlcpy(session->ifname, dev->name, IFNAMSIZ);
 282
 283        dev_hold(dev);
 284        pn = l2tp_eth_pernet(dev_net(dev));
 285        spin_lock(&pn->l2tp_eth_lock);
 286        list_add(&priv->list, &pn->l2tp_eth_dev_list);
 287        spin_unlock(&pn->l2tp_eth_lock);
 288
 289        return 0;
 290
 291out_del_dev:
 292        free_netdev(dev);
 293out_del_session:
 294        l2tp_session_delete(session);
 295out:
 296        return rc;
 297}
 298
 299static __net_init int l2tp_eth_init_net(struct net *net)
 300{
 301        struct l2tp_eth_net *pn = net_generic(net, l2tp_eth_net_id);
 302
 303        INIT_LIST_HEAD(&pn->l2tp_eth_dev_list);
 304        spin_lock_init(&pn->l2tp_eth_lock);
 305
 306        return 0;
 307}
 308
 309static struct pernet_operations l2tp_eth_net_ops = {
 310        .init = l2tp_eth_init_net,
 311        .id   = &l2tp_eth_net_id,
 312        .size = sizeof(struct l2tp_eth_net),
 313};
 314
 315
 316static const struct l2tp_nl_cmd_ops l2tp_eth_nl_cmd_ops = {
 317        .session_create = l2tp_eth_create,
 318        .session_delete = l2tp_session_delete,
 319};
 320
 321
 322static int __init l2tp_eth_init(void)
 323{
 324        int err = 0;
 325
 326        err = l2tp_nl_register_ops(L2TP_PWTYPE_ETH, &l2tp_eth_nl_cmd_ops);
 327        if (err)
 328                goto out;
 329
 330        err = register_pernet_device(&l2tp_eth_net_ops);
 331        if (err)
 332                goto out_unreg;
 333
 334        pr_info("L2TP ethernet pseudowire support (L2TPv3)\n");
 335
 336        return 0;
 337
 338out_unreg:
 339        l2tp_nl_unregister_ops(L2TP_PWTYPE_ETH);
 340out:
 341        return err;
 342}
 343
 344static void __exit l2tp_eth_exit(void)
 345{
 346        unregister_pernet_device(&l2tp_eth_net_ops);
 347        l2tp_nl_unregister_ops(L2TP_PWTYPE_ETH);
 348}
 349
 350module_init(l2tp_eth_init);
 351module_exit(l2tp_eth_exit);
 352
 353MODULE_LICENSE("GPL");
 354MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
 355MODULE_DESCRIPTION("L2TP ethernet pseudowire driver");
 356MODULE_VERSION("1.0");
 357
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