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#include <linux/module.h>
  13#include <linux/skbuff.h>
  14#include <linux/socket.h>
  15#include <linux/hash.h>
  16#include <linux/l2tp.h>
  17#include <linux/in.h>
  18#include <linux/etherdevice.h>
  19#include <linux/spinlock.h>
  20#include <net/sock.h>
  21#include <net/ip.h>
  22#include <net/icmp.h>
  23#include <net/udp.h>
  24#include <net/inet_common.h>
  25#include <net/inet_hashtables.h>
  26#include <net/tcp_states.h>
  27#include <net/protocol.h>
  28#include <net/xfrm.h>
  29#include <net/net_namespace.h>
  30#include <net/netns/generic.h>
  31
  32#include "l2tp_core.h"
  33
  34/* Default device name. May be overridden by name specified by user */
  35#define L2TP_ETH_DEV_NAME       "l2tpeth%d"
  36
  37/* via netdev_priv() */
  38struct l2tp_eth {
  39        struct net_device       *dev;
  40        struct sock             *tunnel_sock;
  41        struct l2tp_session     *session;
  42        struct list_head        list;
  43};
  44
  45/* via l2tp_session_priv() */
  46struct l2tp_eth_sess {
  47        struct net_device       *dev;
  48};
  49
  50/* per-net private data for this module */
  51static unsigned int l2tp_eth_net_id;
  52struct l2tp_eth_net {
  53        struct list_head l2tp_eth_dev_list;
  54        spinlock_t l2tp_eth_lock;
  55};
  56
  57static inline struct l2tp_eth_net *l2tp_eth_pernet(struct net *net)
  58{
  59        return net_generic(net, l2tp_eth_net_id);
  60}
  61
  62static int l2tp_eth_dev_init(struct net_device *dev)
  63{
  64        struct l2tp_eth *priv = netdev_priv(dev);
  65
  66        priv->dev = dev;
  67        random_ether_addr(dev->dev_addr);
  68        memset(&dev->broadcast[0], 0xff, 6);
  69
  70        return 0;
  71}
  72
  73static void l2tp_eth_dev_uninit(struct net_device *dev)
  74{
  75        struct l2tp_eth *priv = netdev_priv(dev);
  76        struct l2tp_eth_net *pn = l2tp_eth_pernet(dev_net(dev));
  77
  78        spin_lock(&pn->l2tp_eth_lock);
  79        list_del_init(&priv->list);
  80        spin_unlock(&pn->l2tp_eth_lock);
  81        dev_put(dev);
  82}
  83
  84static int l2tp_eth_dev_xmit(struct sk_buff *skb, struct net_device *dev)
  85{
  86        struct l2tp_eth *priv = netdev_priv(dev);
  87        struct l2tp_session *session = priv->session;
  88
  89        l2tp_xmit_skb(session, skb, session->hdr_len);
  90
  91        dev->stats.tx_bytes += skb->len;
  92        dev->stats.tx_packets++;
  93
  94        return 0;
  95}
  96
  97static struct net_device_ops l2tp_eth_netdev_ops = {
  98        .ndo_init               = l2tp_eth_dev_init,
  99        .ndo_uninit             = l2tp_eth_dev_uninit,
 100        .ndo_start_xmit         = l2tp_eth_dev_xmit,
 101};
 102
 103static void l2tp_eth_dev_setup(struct net_device *dev)
 104{
 105        ether_setup(dev);
 106
 107        dev->netdev_ops         = &l2tp_eth_netdev_ops;
 108        dev->destructor         = free_netdev;
 109}
 110
 111static void l2tp_eth_dev_recv(struct l2tp_session *session, struct sk_buff *skb, int data_len)
 112{
 113        struct l2tp_eth_sess *spriv = l2tp_session_priv(session);
 114        struct net_device *dev = spriv->dev;
 115
 116        if (session->debug & L2TP_MSG_DATA) {
 117                unsigned int length;
 118                int offset;
 119                u8 *ptr = skb->data;
 120
 121                length = min(32u, skb->len);
 122                if (!pskb_may_pull(skb, length))
 123                        goto error;
 124
 125                printk(KERN_DEBUG "%s: eth recv: ", session->name);
 126
 127                offset = 0;
 128                do {
 129                        printk(" %02X", ptr[offset]);
 130                } while (++offset < length);
 131
 132                printk("\n");
 133        }
 134
 135        if (!pskb_may_pull(skb, sizeof(ETH_HLEN)))
 136                goto error;
 137
 138        secpath_reset(skb);
 139
 140        /* checksums verified by L2TP */
 141        skb->ip_summed = CHECKSUM_NONE;
 142
 143        skb_dst_drop(skb);
 144        nf_reset(skb);
 145
 146        if (dev_forward_skb(dev, skb) == NET_RX_SUCCESS) {
 147                dev->stats.rx_packets++;
 148                dev->stats.rx_bytes += data_len;
 149        } else
 150                dev->stats.rx_errors++;
 151
 152        return;
 153
 154error:
 155        dev->stats.rx_errors++;
 156        kfree_skb(skb);
 157}
 158
 159static void l2tp_eth_delete(struct l2tp_session *session)
 160{
 161        struct l2tp_eth_sess *spriv;
 162        struct net_device *dev;
 163
 164        if (session) {
 165                spriv = l2tp_session_priv(session);
 166                dev = spriv->dev;
 167                if (dev) {
 168                        unregister_netdev(dev);
 169                        spriv->dev = NULL;
 170                }
 171        }
 172}
 173
 174#if defined(CONFIG_L2TP_DEBUGFS) || defined(CONFIG_L2TP_DEBUGFS_MODULE)
 175static void l2tp_eth_show(struct seq_file *m, void *arg)
 176{
 177        struct l2tp_session *session = arg;
 178        struct l2tp_eth_sess *spriv = l2tp_session_priv(session);
 179        struct net_device *dev = spriv->dev;
 180
 181        seq_printf(m, "   interface %s\n", dev->name);
 182}
 183#endif
 184
 185static int l2tp_eth_create(struct net *net, u32 tunnel_id, u32 session_id, u32 peer_session_id, struct l2tp_session_cfg *cfg)
 186{
 187        struct net_device *dev;
 188        char name[IFNAMSIZ];
 189        struct l2tp_tunnel *tunnel;
 190        struct l2tp_session *session;
 191        struct l2tp_eth *priv;
 192        struct l2tp_eth_sess *spriv;
 193        int rc;
 194        struct l2tp_eth_net *pn;
 195
 196        tunnel = l2tp_tunnel_find(net, tunnel_id);
 197        if (!tunnel) {
 198                rc = -ENODEV;
 199                goto out;
 200        }
 201
 202        session = l2tp_session_find(net, tunnel, session_id);
 203        if (session) {
 204                rc = -EEXIST;
 205                goto out;
 206        }
 207
 208        if (cfg->ifname) {
 209                dev = dev_get_by_name(net, cfg->ifname);
 210                if (dev) {
 211                        dev_put(dev);
 212                        rc = -EEXIST;
 213                        goto out;
 214                }
 215                strlcpy(name, cfg->ifname, IFNAMSIZ);
 216        } else
 217                strcpy(name, L2TP_ETH_DEV_NAME);
 218
 219        session = l2tp_session_create(sizeof(*spriv), tunnel, session_id,
 220                                      peer_session_id, cfg);
 221        if (!session) {
 222                rc = -ENOMEM;
 223                goto out;
 224        }
 225
 226        dev = alloc_netdev(sizeof(*priv), name, l2tp_eth_dev_setup);
 227        if (!dev) {
 228                rc = -ENOMEM;
 229                goto out_del_session;
 230        }
 231
 232        dev_net_set(dev, net);
 233        if (session->mtu == 0)
 234                session->mtu = dev->mtu - session->hdr_len;
 235        dev->mtu = session->mtu;
 236        dev->needed_headroom += session->hdr_len;
 237
 238        priv = netdev_priv(dev);
 239        priv->dev = dev;
 240        priv->session = session;
 241        INIT_LIST_HEAD(&priv->list);
 242
 243        priv->tunnel_sock = tunnel->sock;
 244        session->recv_skb = l2tp_eth_dev_recv;
 245        session->session_close = l2tp_eth_delete;
 246#if defined(CONFIG_L2TP_DEBUGFS) || defined(CONFIG_L2TP_DEBUGFS_MODULE)
 247        session->show = l2tp_eth_show;
 248#endif
 249
 250        spriv = l2tp_session_priv(session);
 251        spriv->dev = dev;
 252
 253        rc = register_netdev(dev);
 254        if (rc < 0)
 255                goto out_del_dev;
 256
 257        /* Must be done after register_netdev() */
 258        strlcpy(session->ifname, dev->name, IFNAMSIZ);
 259
 260        dev_hold(dev);
 261        pn = l2tp_eth_pernet(dev_net(dev));
 262        spin_lock(&pn->l2tp_eth_lock);
 263        list_add(&priv->list, &pn->l2tp_eth_dev_list);
 264        spin_unlock(&pn->l2tp_eth_lock);
 265
 266        return 0;
 267
 268out_del_dev:
 269        free_netdev(dev);
 270out_del_session:
 271        l2tp_session_delete(session);
 272out:
 273        return rc;
 274}
 275
 276static __net_init int l2tp_eth_init_net(struct net *net)
 277{
 278        struct l2tp_eth_net *pn = net_generic(net, l2tp_eth_net_id);
 279
 280        INIT_LIST_HEAD(&pn->l2tp_eth_dev_list);
 281        spin_lock_init(&pn->l2tp_eth_lock);
 282
 283        return 0;
 284}
 285
 286static __net_initdata struct pernet_operations l2tp_eth_net_ops = {
 287        .init = l2tp_eth_init_net,
 288        .id   = &l2tp_eth_net_id,
 289        .size = sizeof(struct l2tp_eth_net),
 290};
 291
 292
 293static const struct l2tp_nl_cmd_ops l2tp_eth_nl_cmd_ops = {
 294        .session_create = l2tp_eth_create,
 295        .session_delete = l2tp_session_delete,
 296};
 297
 298
 299static int __init l2tp_eth_init(void)
 300{
 301        int err = 0;
 302
 303        err = l2tp_nl_register_ops(L2TP_PWTYPE_ETH, &l2tp_eth_nl_cmd_ops);
 304        if (err)
 305                goto out;
 306
 307        err = register_pernet_device(&l2tp_eth_net_ops);
 308        if (err)
 309                goto out_unreg;
 310
 311        printk(KERN_INFO "L2TP ethernet pseudowire support (L2TPv3)\n");
 312
 313        return 0;
 314
 315out_unreg:
 316        l2tp_nl_unregister_ops(L2TP_PWTYPE_ETH);
 317out:
 318        return err;
 319}
 320
 321static void __exit l2tp_eth_exit(void)
 322{
 323        unregister_pernet_device(&l2tp_eth_net_ops);
 324        l2tp_nl_unregister_ops(L2TP_PWTYPE_ETH);
 325}
 326
 327module_init(l2tp_eth_init);
 328module_exit(l2tp_eth_exit);
 329
 330MODULE_LICENSE("GPL");
 331MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
 332MODULE_DESCRIPTION("L2TP ethernet pseudowire driver");
 333MODULE_VERSION("1.0");
 334