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