drivers/net/veth.c

   1 /*
   2  *  drivers/net/veth.c
   3  *
   4  *  Copyright (C) 2007 OpenVZ http://openvz.org, SWsoft Inc
   5  *
   6  * Author: Pavel Emelianov <xemul@openvz.org>
   7  * Ethtool interface from: Eric W. Biederman <ebiederm@xmission.com>
   8  *
   9  */
  10
  11 #include <linux/netdevice.h>
  12 #include <linux/slab.h>
  13 #include <linux/ethtool.h>
  14 #include <linux/etherdevice.h>
  15 #include <linux/u64_stats_sync.h>
  16
  17 #include <net/dst.h>
  18 #include <net/xfrm.h>
  19 #include <linux/veth.h>
  20 #include <linux/module.h>
  21
  22 #define DRV_NAME        "veth"
  23 #define DRV_VERSION     "1.0"
  24
  25 #define MIN_MTU 68              /* Min L3 MTU */
  26 #define MAX_MTU 65535           /* Max L3 MTU (arbitrary) */
  27
  28 struct pcpu_vstats {
  29         u64                     packets;
  30         u64                     bytes;
  31         struct u64_stats_sync   syncp;
  32 };
  33
  34 struct veth_priv {
  35         struct net_device __rcu *peer;
  36         atomic64_t              dropped;
  37 };
  38
  39 /*
  40  * ethtool interface
  41  */
  42
  43 static struct {
  44         const char string[ETH_GSTRING_LEN];
  45 } ethtool_stats_keys[] = {
  46         { "peer_ifindex" },
  47 };
  48
  49 static int veth_get_settings(struct net_device *dev, struct ethtool_cmd *cmd)
  50 {
  51         cmd->supported          = 0;
  52         cmd->advertising        = 0;
  53         ethtool_cmd_speed_set(cmd, SPEED_10000);
  54         cmd->duplex             = DUPLEX_FULL;
  55         cmd->port               = PORT_TP;
  56         cmd->phy_address        = 0;
  57         cmd->transceiver        = XCVR_INTERNAL;
  58         cmd->autoneg            = AUTONEG_DISABLE;
  59         cmd->maxtxpkt           = 0;
  60         cmd->maxrxpkt           = 0;
  61         return 0;
  62 }
  63
  64 static void veth_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
  65 {
  66         strlcpy(info->driver, DRV_NAME, sizeof(info->driver));
  67         strlcpy(info->version, DRV_VERSION, sizeof(info->version));
  68 }
  69
  70 static void veth_get_strings(struct net_device *dev, u32 stringset, u8 *buf)
  71 {
  72         switch(stringset) {
  73         case ETH_SS_STATS:
  74                 memcpy(buf, &ethtool_stats_keys, sizeof(ethtool_stats_keys));
  75                 break;
  76         }
  77 }
  78
  79 static int veth_get_sset_count(struct net_device *dev, int sset)
  80 {
  81         switch (sset) {
  82         case ETH_SS_STATS:
  83                 return ARRAY_SIZE(ethtool_stats_keys);
  84         default:
  85                 return -EOPNOTSUPP;
  86         }
  87 }
  88
  89 static void veth_get_ethtool_stats(struct net_device *dev,
  90                 struct ethtool_stats *stats, u64 *data)
  91 {
  92         struct veth_priv *priv = netdev_priv(dev);
  93         struct net_device *peer = rtnl_dereference(priv->peer);
  94
  95         data[0] = peer ? peer->ifindex : 0;
  96 }
  97
  98 static const struct ethtool_ops veth_ethtool_ops = {
  99         .get_settings           = veth_get_settings,
 100         .get_drvinfo            = veth_get_drvinfo,
 101         .get_link               = ethtool_op_get_link,
 102         .get_strings            = veth_get_strings,
 103         .get_sset_count         = veth_get_sset_count,
 104         .get_ethtool_stats      = veth_get_ethtool_stats,
 105 };
 106
 107 static netdev_tx_t veth_xmit(struct sk_buff *skb, struct net_device *dev)
 108 {
 109         struct veth_priv *priv = netdev_priv(dev);
 110         struct net_device *rcv;
 111         int length = skb->len;
 112
 113         rcu_read_lock();
 114         rcv = rcu_dereference(priv->peer);
 115         if (unlikely(!rcv)) {
 116                 kfree_skb(skb);
 117                 goto drop;
 118         }
 119
 120         if (likely(dev_forward_skb(rcv, skb) == NET_RX_SUCCESS)) {
 121                 struct pcpu_vstats *stats = this_cpu_ptr(dev->vstats);
 122
 123                 u64_stats_update_begin(&stats->syncp);
 124                 stats->bytes += length;
 125                 stats->packets++;
 126                 u64_stats_update_end(&stats->syncp);
 127         } else {
 128 drop:
 129                 atomic64_inc(&priv->dropped);
 130         }
 131         rcu_read_unlock();
 132         return NETDEV_TX_OK;
 133 }
 134
 135 /*
 136  * general routines
 137  */
 138
 139 static u64 veth_stats_one(struct pcpu_vstats *result, struct net_device *dev)
 140 {
 141         struct veth_priv *priv = netdev_priv(dev);
 142         int cpu;
 143
 144         result->packets = 0;
 145         result->bytes = 0;
 146         for_each_possible_cpu(cpu) {
 147                 struct pcpu_vstats *stats = per_cpu_ptr(dev->vstats, cpu);
 148                 u64 packets, bytes;
 149                 unsigned int start;
 150
 151                 do {
 152                         start = u64_stats_fetch_begin_bh(&stats->syncp);
 153                         packets = stats->packets;
 154                         bytes = stats->bytes;
 155                 } while (u64_stats_fetch_retry_bh(&stats->syncp, start));
 156                 result->packets += packets;
 157                 result->bytes += bytes;
 158         }
 159         return atomic64_read(&priv->dropped);
 160 }
 161
 162 static struct rtnl_link_stats64 *veth_get_stats64(struct net_device *dev,
 163                                                   struct rtnl_link_stats64 *tot)
 164 {
 165         struct veth_priv *priv = netdev_priv(dev);
 166         struct net_device *peer;
 167         struct pcpu_vstats one;
 168
 169         tot->tx_dropped = veth_stats_one(&one, dev);
 170         tot->tx_bytes = one.bytes;
 171         tot->tx_packets = one.packets;
 172
 173         rcu_read_lock();
 174         peer = rcu_dereference(priv->peer);
 175         if (peer) {
 176                 tot->rx_dropped = veth_stats_one(&one, peer);
 177                 tot->rx_bytes = one.bytes;
 178                 tot->rx_packets = one.packets;
 179         }
 180         rcu_read_unlock();
 181
 182         return tot;
 183 }
 184
 185 static int veth_open(struct net_device *dev)
 186 {
 187         struct veth_priv *priv = netdev_priv(dev);
 188         struct net_device *peer = rtnl_dereference(priv->peer);
 189
 190         if (!peer)
 191                 return -ENOTCONN;
 192
 193         if (peer->flags & IFF_UP) {
 194                 netif_carrier_on(dev);
 195                 netif_carrier_on(peer);
 196         }
 197         return 0;
 198 }
 199
 200 static int veth_close(struct net_device *dev)
 201 {
 202         struct veth_priv *priv = netdev_priv(dev);
 203         struct net_device *peer = rtnl_dereference(priv->peer);
 204
 205         netif_carrier_off(dev);
 206         if (peer)
 207                 netif_carrier_off(peer);
 208
 209         return 0;
 210 }
 211
 212 static int is_valid_veth_mtu(int new_mtu)
 213 {
 214         return new_mtu >= MIN_MTU && new_mtu <= MAX_MTU;
 215 }
 216
 217 static int veth_change_mtu(struct net_device *dev, int new_mtu)
 218 {
 219         if (!is_valid_veth_mtu(new_mtu))
 220                 return -EINVAL;
 221         dev->mtu = new_mtu;
 222         return 0;
 223 }
 224
 225 static int veth_dev_init(struct net_device *dev)
 226 {
 227         dev->vstats = alloc_percpu(struct pcpu_vstats);
 228         if (!dev->vstats)
 229                 return -ENOMEM;
 230
 231         return 0;
 232 }
 233
 234 static void veth_dev_free(struct net_device *dev)
 235 {
 236         free_percpu(dev->vstats);
 237         free_netdev(dev);
 238 }
 239
 240 static const struct net_device_ops veth_netdev_ops = {
 241         .ndo_init            = veth_dev_init,
 242         .ndo_open            = veth_open,
 243         .ndo_stop            = veth_close,
 244         .ndo_start_xmit      = veth_xmit,
 245         .ndo_change_mtu      = veth_change_mtu,
 246         .ndo_get_stats64     = veth_get_stats64,
 247         .ndo_set_mac_address = eth_mac_addr,
 248 };
 249
 250 #define VETH_FEATURES (NETIF_F_SG | NETIF_F_FRAGLIST | NETIF_F_ALL_TSO |    \
 251                        NETIF_F_HW_CSUM | NETIF_F_RXCSUM | NETIF_F_HIGHDMA | \
 252                        NETIF_F_HW_VLAN_CTAG_TX | NETIF_F_HW_VLAN_CTAG_RX | \
 253                        NETIF_F_HW_VLAN_STAG_TX | NETIF_F_HW_VLAN_STAG_RX )
 254
 255 static void veth_setup(struct net_device *dev)
 256 {
 257         ether_setup(dev);
 258
 259         dev->priv_flags &= ~IFF_TX_SKB_SHARING;
 260         dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
 261
 262         dev->netdev_ops = &veth_netdev_ops;
 263         dev->ethtool_ops = &veth_ethtool_ops;
 264         dev->features |= NETIF_F_LLTX;
 265         dev->features |= VETH_FEATURES;
 266         dev->vlan_features = dev->features &
 267                              ~(NETIF_F_HW_VLAN_CTAG_TX | NETIF_F_HW_VLAN_STAG_TX);
 268         dev->destructor = veth_dev_free;
 269
 270         dev->hw_features = VETH_FEATURES;
 271 }
 272
 273 /*
 274  * netlink interface
 275  */
 276
 277 static int veth_validate(struct nlattr *tb[], struct nlattr *data[])
 278 {
 279         if (tb[IFLA_ADDRESS]) {
 280                 if (nla_len(tb[IFLA_ADDRESS]) != ETH_ALEN)
 281                         return -EINVAL;
 282                 if (!is_valid_ether_addr(nla_data(tb[IFLA_ADDRESS])))
 283                         return -EADDRNOTAVAIL;
 284         }
 285         if (tb[IFLA_MTU]) {
 286                 if (!is_valid_veth_mtu(nla_get_u32(tb[IFLA_MTU])))
 287                         return -EINVAL;
 288         }
 289         return 0;
 290 }
 291
 292 static struct rtnl_link_ops veth_link_ops;
 293
 294 static int veth_newlink(struct net *src_net, struct net_device *dev,
 295                          struct nlattr *tb[], struct nlattr *data[])
 296 {
 297         int err;
 298         struct net_device *peer;
 299         struct veth_priv *priv;
 300         char ifname[IFNAMSIZ];
 301         struct nlattr *peer_tb[IFLA_MAX + 1], **tbp;
 302         struct ifinfomsg *ifmp;
 303         struct net *net;
 304
 305         /*
 306          * create and register peer first
 307          */
 308         if (data != NULL && data[VETH_INFO_PEER] != NULL) {
 309                 struct nlattr *nla_peer;
 310
 311                 nla_peer = data[VETH_INFO_PEER];
 312                 ifmp = nla_data(nla_peer);
 313                 err = nla_parse(peer_tb, IFLA_MAX,
 314                                 nla_data(nla_peer) + sizeof(struct ifinfomsg),
 315                                 nla_len(nla_peer) - sizeof(struct ifinfomsg),
 316                                 ifla_policy);
 317                 if (err < 0)
 318                         return err;
 319
 320                 err = veth_validate(peer_tb, NULL);
 321                 if (err < 0)
 322                         return err;
 323
 324                 tbp = peer_tb;
 325         } else {
 326                 ifmp = NULL;
 327                 tbp = tb;
 328         }
 329
 330         if (tbp[IFLA_IFNAME])
 331                 nla_strlcpy(ifname, tbp[IFLA_IFNAME], IFNAMSIZ);
 332         else
 333                 snprintf(ifname, IFNAMSIZ, DRV_NAME "%%d");
 334
 335         net = rtnl_link_get_net(src_net, tbp);
 336         if (IS_ERR(net))
 337                 return PTR_ERR(net);
 338
 339         peer = rtnl_create_link(net, ifname, &veth_link_ops, tbp);
 340         if (IS_ERR(peer)) {
 341                 put_net(net);
 342                 return PTR_ERR(peer);
 343         }
 344
 345         if (tbp[IFLA_ADDRESS] == NULL)
 346                 eth_hw_addr_random(peer);
 347
 348         if (ifmp && (dev->ifindex != 0))
 349                 peer->ifindex = ifmp->ifi_index;
 350
 351         err = register_netdevice(peer);
 352         put_net(net);
 353         net = NULL;
 354         if (err < 0)
 355                 goto err_register_peer;
 356
 357         netif_carrier_off(peer);
 358
 359         err = rtnl_configure_link(peer, ifmp);
 360         if (err < 0)
 361                 goto err_configure_peer;
 362
 363         /*
 364          * register dev last
 365          *
 366          * note, that since we've registered new device the dev's name
 367          * should be re-allocated
 368          */
 369
 370         if (tb[IFLA_ADDRESS] == NULL)
 371                 eth_hw_addr_random(dev);
 372
 373         if (tb[IFLA_IFNAME])
 374                 nla_strlcpy(dev->name, tb[IFLA_IFNAME], IFNAMSIZ);
 375         else
 376                 snprintf(dev->name, IFNAMSIZ, DRV_NAME "%%d");
 377
 378         err = register_netdevice(dev);
 379         if (err < 0)
 380                 goto err_register_dev;
 381
 382         netif_carrier_off(dev);
 383
 384         /*
 385          * tie the deviced together
 386          */
 387
 388         priv = netdev_priv(dev);
 389         rcu_assign_pointer(priv->peer, peer);
 390
 391         priv = netdev_priv(peer);
 392         rcu_assign_pointer(priv->peer, dev);
 393         return 0;
 394
 395 err_register_dev:
 396         /* nothing to do */
 397 err_configure_peer:
 398         unregister_netdevice(peer);
 399         return err;
 400
 401 err_register_peer:
 402         free_netdev(peer);
 403         return err;
 404 }
 405
 406 static void veth_dellink(struct net_device *dev, struct list_head *head)
 407 {
 408         struct veth_priv *priv;
 409         struct net_device *peer;
 410
 411         priv = netdev_priv(dev);
 412         peer = rtnl_dereference(priv->peer);
 413
 414         /* Note : dellink() is called from default_device_exit_batch(),
 415          * before a rcu_synchronize() point. The devices are guaranteed
 416          * not being freed before one RCU grace period.
 417          */
 418         RCU_INIT_POINTER(priv->peer, NULL);
 419         unregister_netdevice_queue(dev, head);
 420
 421         if (peer) {
 422                 priv = netdev_priv(peer);
 423                 RCU_INIT_POINTER(priv->peer, NULL);
 424                 unregister_netdevice_queue(peer, head);
 425         }
 426 }
 427
 428 static const struct nla_policy veth_policy[VETH_INFO_MAX + 1] = {
 429         [VETH_INFO_PEER]        = { .len = sizeof(struct ifinfomsg) },
 430 };
 431
 432 static struct rtnl_link_ops veth_link_ops = {
 433         .kind           = DRV_NAME,
 434         .priv_size      = sizeof(struct veth_priv),
 435         .setup          = veth_setup,
 436         .validate       = veth_validate,
 437         .newlink        = veth_newlink,
 438         .dellink        = veth_dellink,
 439         .policy         = veth_policy,
 440         .maxtype        = VETH_INFO_MAX,
 441 };
 442
 443 /*
 444  * init/fini
 445  */
 446
 447 static __init int veth_init(void)
 448 {
 449         return rtnl_link_register(&veth_link_ops);
 450 }
 451
 452 static __exit void veth_exit(void)
 453 {
 454         rtnl_link_unregister(&veth_link_ops);
 455 }
 456
 457 module_init(veth_init);
 458 module_exit(veth_exit);
 459
 460 MODULE_DESCRIPTION("Virtual Ethernet Tunnel");
 461 MODULE_LICENSE("GPL v2");
 462 MODULE_ALIAS_RTNL_LINK(DRV_NAME);