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 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
  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 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
 124 static 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
 131 static 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
 140 static 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
 176 error:
 177         atomic_long_inc(&priv->rx_errors);
 178         kfree_skb(skb);
 179 }
 180
 181 static 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)
 198 static 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
 208 static 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
 292 out_del_dev:
 293         free_netdev(dev);
 294         spriv->dev = NULL;
 295 out_del_session:
 296         l2tp_session_delete(session);
 297 out:
 298         return rc;
 299 }
 300
 301 static __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
 311 static 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
 318 static 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
 324 static 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
 340 out_unreg:
 341         l2tp_nl_unregister_ops(L2TP_PWTYPE_ETH);
 342 out:
 343         return err;
 344 }
 345
 346 static 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
 352 module_init(l2tp_eth_init);
 353 module_exit(l2tp_eth_exit);
 354
 355 MODULE_LICENSE("GPL");
 356 MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
 357 MODULE_DESCRIPTION("L2TP ethernet pseudowire driver");
 358 MODULE_VERSION("1.0");