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           rx_bytes;
  48         atomic_long_t           rx_packets;
  49         atomic_long_t           rx_errors;
  50 };
  51
  52 /* via l2tp_session_priv() */
  53 struct l2tp_eth_sess {
  54         struct net_device       *dev;
  55 };
  56
  57 /* per-net private data for this module */
  58 static unsigned int l2tp_eth_net_id;
  59 struct l2tp_eth_net {
  60         struct list_head l2tp_eth_dev_list;
  61         spinlock_t l2tp_eth_lock;
  62 };
  63
  64 static inline struct l2tp_eth_net *l2tp_eth_pernet(struct net *net)
  65 {
  66         return net_generic(net, l2tp_eth_net_id);
  67 }
  68
  69 static int l2tp_eth_dev_init(struct net_device *dev)
  70 {
  71         struct l2tp_eth *priv = netdev_priv(dev);
  72
  73         priv->dev = dev;
  74         eth_hw_addr_random(dev);
  75         memset(&dev->broadcast[0], 0xff, 6);
  76
  77         return 0;
  78 }
  79
  80 static void l2tp_eth_dev_uninit(struct net_device *dev)
  81 {
  82         struct l2tp_eth *priv = netdev_priv(dev);
  83         struct l2tp_eth_net *pn = l2tp_eth_pernet(dev_net(dev));
  84
  85         spin_lock(&pn->l2tp_eth_lock);
  86         list_del_init(&priv->list);
  87         spin_unlock(&pn->l2tp_eth_lock);
  88         dev_put(dev);
  89 }
  90
  91 static int l2tp_eth_dev_xmit(struct sk_buff *skb, struct net_device *dev)
  92 {
  93         struct l2tp_eth *priv = netdev_priv(dev);
  94         struct l2tp_session *session = priv->session;
  95
  96         atomic_long_add(skb->len, &priv->tx_bytes);
  97         atomic_long_inc(&priv->tx_packets);
  98
  99         l2tp_xmit_skb(session, skb, session->hdr_len);
 100
 101         return NETDEV_TX_OK;
 102 }
 103
 104 static struct rtnl_link_stats64 *l2tp_eth_get_stats64(struct net_device *dev,
 105                                                       struct rtnl_link_stats64 *stats)
 106 {
 107         struct l2tp_eth *priv = netdev_priv(dev);
 108
 109         stats->tx_bytes   = atomic_long_read(&priv->tx_bytes);
 110         stats->tx_packets = atomic_long_read(&priv->tx_packets);
 111         stats->rx_bytes   = atomic_long_read(&priv->rx_bytes);
 112         stats->rx_packets = atomic_long_read(&priv->rx_packets);
 113         stats->rx_errors  = atomic_long_read(&priv->rx_errors);
 114         return stats;
 115 }
 116
 117
 118 static struct net_device_ops l2tp_eth_netdev_ops = {
 119         .ndo_init               = l2tp_eth_dev_init,
 120         .ndo_uninit             = l2tp_eth_dev_uninit,
 121         .ndo_start_xmit         = l2tp_eth_dev_xmit,
 122         .ndo_get_stats64        = l2tp_eth_get_stats64,
 123 };
 124
 125 static void l2tp_eth_dev_setup(struct net_device *dev)
 126 {
 127         ether_setup(dev);
 128         dev->priv_flags         &= ~IFF_TX_SKB_SHARING;
 129         dev->features           |= NETIF_F_LLTX;
 130         dev->netdev_ops         = &l2tp_eth_netdev_ops;
 131         dev->destructor         = free_netdev;
 132 }
 133
 134 static void l2tp_eth_dev_recv(struct l2tp_session *session, struct sk_buff *skb, int data_len)
 135 {
 136         struct l2tp_eth_sess *spriv = l2tp_session_priv(session);
 137         struct net_device *dev = spriv->dev;
 138         struct l2tp_eth *priv = netdev_priv(dev);
 139
 140         if (session->debug & L2TP_MSG_DATA) {
 141                 unsigned int length;
 142
 143                 length = min(32u, skb->len);
 144                 if (!pskb_may_pull(skb, length))
 145                         goto error;
 146
 147                 pr_debug("%s: eth recv\n", session->name);
 148                 print_hex_dump_bytes("", DUMP_PREFIX_OFFSET, skb->data, length);
 149         }
 150
 151         if (!pskb_may_pull(skb, sizeof(ETH_HLEN)))
 152                 goto error;
 153
 154         secpath_reset(skb);
 155
 156         /* checksums verified by L2TP */
 157         skb->ip_summed = CHECKSUM_NONE;
 158
 159         skb_dst_drop(skb);
 160         nf_reset(skb);
 161
 162         if (dev_forward_skb(dev, skb) == NET_RX_SUCCESS) {
 163                 atomic_long_inc(&priv->rx_packets);
 164                 atomic_long_add(data_len, &priv->rx_bytes);
 165         } else {
 166                 atomic_long_inc(&priv->rx_errors);
 167         }
 168         return;
 169
 170 error:
 171         atomic_long_inc(&priv->rx_errors);
 172         kfree_skb(skb);
 173 }
 174
 175 static void l2tp_eth_delete(struct l2tp_session *session)
 176 {
 177         struct l2tp_eth_sess *spriv;
 178         struct net_device *dev;
 179
 180         if (session) {
 181                 spriv = l2tp_session_priv(session);
 182                 dev = spriv->dev;
 183                 if (dev) {
 184                         unregister_netdev(dev);
 185                         spriv->dev = NULL;
 186                         module_put(THIS_MODULE);
 187                 }
 188         }
 189 }
 190
 191 #if defined(CONFIG_L2TP_DEBUGFS) || defined(CONFIG_L2TP_DEBUGFS_MODULE)
 192 static void l2tp_eth_show(struct seq_file *m, void *arg)
 193 {
 194         struct l2tp_session *session = arg;
 195         struct l2tp_eth_sess *spriv = l2tp_session_priv(session);
 196         struct net_device *dev = spriv->dev;
 197
 198         seq_printf(m, "   interface %s\n", dev->name);
 199 }
 200 #endif
 201
 202 static int l2tp_eth_create(struct net *net, u32 tunnel_id, u32 session_id, u32 peer_session_id, struct l2tp_session_cfg *cfg)
 203 {
 204         struct net_device *dev;
 205         char name[IFNAMSIZ];
 206         struct l2tp_tunnel *tunnel;
 207         struct l2tp_session *session;
 208         struct l2tp_eth *priv;
 209         struct l2tp_eth_sess *spriv;
 210         int rc;
 211         struct l2tp_eth_net *pn;
 212
 213         tunnel = l2tp_tunnel_find(net, tunnel_id);
 214         if (!tunnel) {
 215                 rc = -ENODEV;
 216                 goto out;
 217         }
 218
 219         session = l2tp_session_find(net, tunnel, session_id);
 220         if (session) {
 221                 rc = -EEXIST;
 222                 goto out;
 223         }
 224
 225         if (cfg->ifname) {
 226                 dev = dev_get_by_name(net, cfg->ifname);
 227                 if (dev) {
 228                         dev_put(dev);
 229                         rc = -EEXIST;
 230                         goto out;
 231                 }
 232                 strlcpy(name, cfg->ifname, IFNAMSIZ);
 233         } else
 234                 strcpy(name, L2TP_ETH_DEV_NAME);
 235
 236         session = l2tp_session_create(sizeof(*spriv), tunnel, session_id,
 237                                       peer_session_id, cfg);
 238         if (!session) {
 239                 rc = -ENOMEM;
 240                 goto out;
 241         }
 242
 243         dev = alloc_netdev(sizeof(*priv), name, l2tp_eth_dev_setup);
 244         if (!dev) {
 245                 rc = -ENOMEM;
 246                 goto out_del_session;
 247         }
 248
 249         dev_net_set(dev, net);
 250         if (session->mtu == 0)
 251                 session->mtu = dev->mtu - session->hdr_len;
 252         dev->mtu = session->mtu;
 253         dev->needed_headroom += session->hdr_len;
 254
 255         priv = netdev_priv(dev);
 256         priv->dev = dev;
 257         priv->session = session;
 258         INIT_LIST_HEAD(&priv->list);
 259
 260         priv->tunnel_sock = tunnel->sock;
 261         session->recv_skb = l2tp_eth_dev_recv;
 262         session->session_close = l2tp_eth_delete;
 263 #if defined(CONFIG_L2TP_DEBUGFS) || defined(CONFIG_L2TP_DEBUGFS_MODULE)
 264         session->show = l2tp_eth_show;
 265 #endif
 266
 267         spriv = l2tp_session_priv(session);
 268         spriv->dev = dev;
 269
 270         rc = register_netdev(dev);
 271         if (rc < 0)
 272                 goto out_del_dev;
 273
 274         __module_get(THIS_MODULE);
 275         /* Must be done after register_netdev() */
 276         strlcpy(session->ifname, dev->name, IFNAMSIZ);
 277
 278         dev_hold(dev);
 279         pn = l2tp_eth_pernet(dev_net(dev));
 280         spin_lock(&pn->l2tp_eth_lock);
 281         list_add(&priv->list, &pn->l2tp_eth_dev_list);
 282         spin_unlock(&pn->l2tp_eth_lock);
 283
 284         return 0;
 285
 286 out_del_dev:
 287         free_netdev(dev);
 288 out_del_session:
 289         l2tp_session_delete(session);
 290 out:
 291         return rc;
 292 }
 293
 294 static __net_init int l2tp_eth_init_net(struct net *net)
 295 {
 296         struct l2tp_eth_net *pn = net_generic(net, l2tp_eth_net_id);
 297
 298         INIT_LIST_HEAD(&pn->l2tp_eth_dev_list);
 299         spin_lock_init(&pn->l2tp_eth_lock);
 300
 301         return 0;
 302 }
 303
 304 static struct pernet_operations l2tp_eth_net_ops = {
 305         .init = l2tp_eth_init_net,
 306         .id   = &l2tp_eth_net_id,
 307         .size = sizeof(struct l2tp_eth_net),
 308 };
 309
 310
 311 static const struct l2tp_nl_cmd_ops l2tp_eth_nl_cmd_ops = {
 312         .session_create = l2tp_eth_create,
 313         .session_delete = l2tp_session_delete,
 314 };
 315
 316
 317 static int __init l2tp_eth_init(void)
 318 {
 319         int err = 0;
 320
 321         err = l2tp_nl_register_ops(L2TP_PWTYPE_ETH, &l2tp_eth_nl_cmd_ops);
 322         if (err)
 323                 goto out;
 324
 325         err = register_pernet_device(&l2tp_eth_net_ops);
 326         if (err)
 327                 goto out_unreg;
 328
 329         pr_info("L2TP ethernet pseudowire support (L2TPv3)\n");
 330
 331         return 0;
 332
 333 out_unreg:
 334         l2tp_nl_unregister_ops(L2TP_PWTYPE_ETH);
 335 out:
 336         return err;
 337 }
 338
 339 static void __exit l2tp_eth_exit(void)
 340 {
 341         unregister_pernet_device(&l2tp_eth_net_ops);
 342         l2tp_nl_unregister_ops(L2TP_PWTYPE_ETH);
 343 }
 344
 345 module_init(l2tp_eth_init);
 346 module_exit(l2tp_eth_exit);
 347
 348 MODULE_LICENSE("GPL");
 349 MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
 350 MODULE_DESCRIPTION("L2TP ethernet pseudowire driver");
 351 MODULE_VERSION("1.0");