--- /dev/null
+/*
+ *  drivers/net/veth.c
+ *
+ *  Copyright (C) 2007 OpenVZ http://openvz.org, SWsoft Inc
+ *
+ * Author: Pavel Emelianov <xemul@openvz.org>
+ * Ethtool interface from: Eric W. Biederman <ebiederm@xmission.com>
+ *
+ */
+
+#include <linux/list.h>
+#include <linux/netdevice.h>
+#include <linux/ethtool.h>
+#include <linux/etherdevice.h>
+
+#include <net/dst.h>
+#include <net/xfrm.h>
+#include <net/veth.h>
+
+#define DRV_NAME       "veth"
+#define DRV_VERSION    "1.0"
+
+struct veth_net_stats {
+       unsigned long   rx_packets;
+       unsigned long   tx_packets;
+       unsigned long   rx_bytes;
+       unsigned long   tx_bytes;
+       unsigned long   tx_dropped;
+};
+
+struct veth_priv {
+       struct net_device *peer;
+       struct net_device *dev;
+       struct list_head list;
+       struct veth_net_stats *stats;
+       unsigned ip_summed;
+};
+
+static LIST_HEAD(veth_list);
+
+/*
+ * ethtool interface
+ */
+
+static struct {
+       const char string[ETH_GSTRING_LEN];
+} ethtool_stats_keys[] = {
+       { "peer_ifindex" },
+};
+
+static int veth_get_settings(struct net_device *dev, struct ethtool_cmd *cmd)
+{
+       cmd->supported          = 0;
+       cmd->advertising        = 0;
+       cmd->speed              = SPEED_10000;
+       cmd->duplex             = DUPLEX_FULL;
+       cmd->port               = PORT_TP;
+       cmd->phy_address        = 0;
+       cmd->transceiver        = XCVR_INTERNAL;
+       cmd->autoneg            = AUTONEG_DISABLE;
+       cmd->maxtxpkt           = 0;
+       cmd->maxrxpkt           = 0;
+       return 0;
+}
+
+static void veth_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
+{
+       strcpy(info->driver, DRV_NAME);
+       strcpy(info->version, DRV_VERSION);
+       strcpy(info->fw_version, "N/A");
+}
+
+static void veth_get_strings(struct net_device *dev, u32 stringset, u8 *buf)
+{
+       switch(stringset) {
+       case ETH_SS_STATS:
+               memcpy(buf, ðtool_stats_keys, sizeof(ethtool_stats_keys));
+               break;
+       }
+}
+
+static int veth_get_stats_count(struct net_device *dev)
+{
+       return ARRAY_SIZE(ethtool_stats_keys);
+}
+
+static void veth_get_ethtool_stats(struct net_device *dev,
+               struct ethtool_stats *stats, u64 *data)
+{
+       struct veth_priv *priv;
+
+       priv = netdev_priv(dev);
+       data[0] = priv->peer->ifindex;
+}
+
+static u32 veth_get_rx_csum(struct net_device *dev)
+{
+       struct veth_priv *priv;
+
+       priv = netdev_priv(dev);
+       return priv->ip_summed == CHECKSUM_UNNECESSARY;
+}
+
+static int veth_set_rx_csum(struct net_device *dev, u32 data)
+{
+       struct veth_priv *priv;
+
+       priv = netdev_priv(dev);
+       priv->ip_summed = data ? CHECKSUM_UNNECESSARY : CHECKSUM_NONE;
+       return 0;
+}
+
+static u32 veth_get_tx_csum(struct net_device *dev)
+{
+       return (dev->features & NETIF_F_NO_CSUM) != 0;
+}
+
+static int veth_set_tx_csum(struct net_device *dev, u32 data)
+{
+       if (data)
+               dev->features |= NETIF_F_NO_CSUM;
+       else
+               dev->features &= ~NETIF_F_NO_CSUM;
+       return 0;
+}
+
+static struct ethtool_ops veth_ethtool_ops = {
+       .get_settings           = veth_get_settings,
+       .get_drvinfo            = veth_get_drvinfo,
+       .get_link               = ethtool_op_get_link,
+       .get_rx_csum            = veth_get_rx_csum,
+       .set_rx_csum            = veth_set_rx_csum,
+       .get_tx_csum            = veth_get_tx_csum,
+       .set_tx_csum            = veth_set_tx_csum,
+       .get_sg                 = ethtool_op_get_sg,
+       .set_sg                 = ethtool_op_set_sg,
+       .get_strings            = veth_get_strings,
+       .get_stats_count        = veth_get_stats_count,
+       .get_ethtool_stats      = veth_get_ethtool_stats,
+};
+
+/*
+ * xmit
+ */
+
+static int veth_xmit(struct sk_buff *skb, struct net_device *dev)
+{
+       struct net_device *rcv = NULL;
+       struct veth_priv *priv, *rcv_priv;
+       struct veth_net_stats *stats;
+       int length, cpu;
+
+       skb_orphan(skb);
+
+       priv = netdev_priv(dev);
+       rcv = priv->peer;
+       rcv_priv = netdev_priv(rcv);
+
+       cpu = smp_processor_id();
+       stats = per_cpu_ptr(priv->stats, cpu);
+
+       if (!(rcv->flags & IFF_UP))
+               goto outf;
+
+       skb->pkt_type = PACKET_HOST;
+       skb->protocol = eth_type_trans(skb, rcv);
+       if (dev->features & NETIF_F_NO_CSUM)
+               skb->ip_summed = rcv_priv->ip_summed;
+
+       dst_release(skb->dst);
+       skb->dst = NULL;
+       skb->mark = 0;
+       secpath_reset(skb);
+       nf_reset(skb);
+
+       length = skb->len;
+
+       stats->tx_bytes += length;
+       stats->tx_packets++;
+
+       stats = per_cpu_ptr(rcv_priv->stats, cpu);
+       stats->rx_bytes += length;
+       stats->rx_packets++;
+
+       netif_rx(skb);
+       return 0;
+
+outf:
+       kfree_skb(skb);
+       stats->tx_dropped++;
+       return 0;
+}
+
+/*
+ * general routines
+ */
+
+static struct net_device_stats *veth_get_stats(struct net_device *dev)
+{
+       struct veth_priv *priv;
+       struct net_device_stats *dev_stats;
+       int cpu;
+       struct veth_net_stats *stats;
+
+       priv = netdev_priv(dev);
+       dev_stats = &dev->stats;
+
+       dev_stats->rx_packets = 0;
+       dev_stats->tx_packets = 0;
+       dev_stats->rx_bytes = 0;
+       dev_stats->tx_bytes = 0;
+       dev_stats->tx_dropped = 0;
+
+       for_each_online_cpu(cpu) {
+               stats = per_cpu_ptr(priv->stats, cpu);
+
+               dev_stats->rx_packets += stats->rx_packets;
+               dev_stats->tx_packets += stats->tx_packets;
+               dev_stats->rx_bytes += stats->rx_bytes;
+               dev_stats->tx_bytes += stats->tx_bytes;
+               dev_stats->tx_dropped += stats->tx_dropped;
+       }
+
+       return dev_stats;
+}
+
+static int veth_open(struct net_device *dev)
+{
+       struct veth_priv *priv;
+
+       priv = netdev_priv(dev);
+       if (priv->peer == NULL)
+               return -ENOTCONN;
+
+       if (priv->peer->flags & IFF_UP) {
+               netif_carrier_on(dev);
+               netif_carrier_on(priv->peer);
+       }
+       return 0;
+}
+
+static int veth_close(struct net_device *dev)
+{
+       struct veth_priv *priv;
+
+       if (netif_carrier_ok(dev)) {
+               priv = netdev_priv(dev);
+               netif_carrier_off(dev);
+               netif_carrier_off(priv->peer);
+       }
+       return 0;
+}
+
+static int veth_dev_init(struct net_device *dev)
+{
+       struct veth_net_stats *stats;
+       struct veth_priv *priv;
+
+       stats = alloc_percpu(struct veth_net_stats);
+       if (stats == NULL)
+               return -ENOMEM;
+
+       priv = netdev_priv(dev);
+       priv->stats = stats;
+       return 0;
+}
+
+static void veth_dev_free(struct net_device *dev)
+{
+       struct veth_priv *priv;
+
+       priv = netdev_priv(dev);
+       free_percpu(priv->stats);
+       free_netdev(dev);
+}
+
+static void veth_setup(struct net_device *dev)
+{
+       ether_setup(dev);
+
+       dev->hard_start_xmit = veth_xmit;
+       dev->get_stats = veth_get_stats;
+       dev->open = veth_open;
+       dev->stop = veth_close;
+       dev->ethtool_ops = &veth_ethtool_ops;
+       dev->features |= NETIF_F_LLTX;
+       dev->init = veth_dev_init;
+       dev->destructor = veth_dev_free;
+}
+
+/*
+ * netlink interface
+ */
+
+static int veth_validate(struct nlattr *tb[], struct nlattr *data[])
+{
+       if (tb[IFLA_ADDRESS]) {
+               if (nla_len(tb[IFLA_ADDRESS]) != ETH_ALEN)
+                       return -EINVAL;
+               if (!is_valid_ether_addr(nla_data(tb[IFLA_ADDRESS])))
+                       return -EADDRNOTAVAIL;
+       }
+       return 0;
+}
+
+static struct rtnl_link_ops veth_link_ops;
+
+static int veth_newlink(struct net_device *dev,
+                        struct nlattr *tb[], struct nlattr *data[])
+{
+       int err;
+       struct net_device *peer;
+       struct veth_priv *priv;
+       char ifname[IFNAMSIZ];
+       struct nlattr *peer_tb[IFLA_MAX + 1], **tbp;
+
+       /*
+        * create and register peer first
+        *
+        * struct ifinfomsg is at the head of VETH_INFO_PEER, but we
+        * skip it since no info from it is useful yet
+        */
+
+       if (data != NULL && data[VETH_INFO_PEER] != NULL) {
+               struct nlattr *nla_peer;
+
+               nla_peer = data[VETH_INFO_PEER];
+               err = nla_parse(peer_tb, IFLA_MAX,
+                               nla_data(nla_peer) + sizeof(struct ifinfomsg),
+                               nla_len(nla_peer) - sizeof(struct ifinfomsg),
+                               ifla_policy);
+               if (err < 0)
+                       return err;
+
+               err = veth_validate(peer_tb, NULL);
+               if (err < 0)
+                       return err;
+
+               tbp = peer_tb;
+       } else
+               tbp = tb;
+
+       if (tbp[IFLA_IFNAME])
+               nla_strlcpy(ifname, tbp[IFLA_IFNAME], IFNAMSIZ);
+       else
+               snprintf(ifname, IFNAMSIZ, DRV_NAME "%%d");
+
+       peer = rtnl_create_link(ifname, &veth_link_ops, tbp);
+       if (IS_ERR(peer))
+               return PTR_ERR(peer);
+
+       if (tbp[IFLA_ADDRESS] == NULL)
+               random_ether_addr(peer->dev_addr);
+
+       err = register_netdevice(peer);
+       if (err < 0)
+               goto err_register_peer;
+
+       netif_carrier_off(peer);
+
+       /*
+        * register dev last
+        *
+        * note, that since we've registered new device the dev's name
+        * should be re-allocated
+        */
+
+       if (tb[IFLA_ADDRESS] == NULL)
+               random_ether_addr(dev->dev_addr);
+
+       if (tb[IFLA_IFNAME])
+               nla_strlcpy(dev->name, tb[IFLA_IFNAME], IFNAMSIZ);
+       else
+               snprintf(dev->name, IFNAMSIZ, DRV_NAME "%%d");
+
+       if (strchr(dev->name, '%')) {
+               err = dev_alloc_name(dev, dev->name);
+               if (err < 0)
+                       goto err_alloc_name;
+       }
+
+       err = register_netdevice(dev);
+       if (err < 0)
+               goto err_register_dev;
+
+       netif_carrier_off(dev);
+
+       /*
+        * tie the deviced together
+        */
+
+       priv = netdev_priv(dev);
+       priv->dev = dev;
+       priv->peer = peer;
+       list_add(&priv->list, &veth_list);
+
+       priv = netdev_priv(peer);
+       priv->dev = peer;
+       priv->peer = dev;
+       INIT_LIST_HEAD(&priv->list);
+       return 0;
+
+err_register_dev:
+       /* nothing to do */
+err_alloc_name:
+       unregister_netdevice(peer);
+       return err;
+
+err_register_peer:
+       free_netdev(peer);
+       return err;
+}
+
+static void veth_dellink(struct net_device *dev)
+{
+       struct veth_priv *priv;
+       struct net_device *peer;
+
+       priv = netdev_priv(dev);
+       peer = priv->peer;
+
+       if (!list_empty(&priv->list))
+               list_del(&priv->list);
+
+       priv = netdev_priv(peer);
+       if (!list_empty(&priv->list))
+               list_del(&priv->list);
+
+       unregister_netdevice(dev);
+       unregister_netdevice(peer);
+}
+
+static const struct nla_policy veth_policy[VETH_INFO_MAX + 1];
+
+static struct rtnl_link_ops veth_link_ops = {
+       .kind           = DRV_NAME,
+       .priv_size      = sizeof(struct veth_priv),
+       .setup          = veth_setup,
+       .validate       = veth_validate,
+       .newlink        = veth_newlink,
+       .dellink        = veth_dellink,
+       .policy         = veth_policy,
+       .maxtype        = VETH_INFO_MAX,
+};
+
+/*
+ * init/fini
+ */
+
+static __init int veth_init(void)
+{
+       return rtnl_link_register(&veth_link_ops);
+}
+
+static __exit void veth_exit(void)
+{
+       struct veth_priv *priv, *next;
+
+       rtnl_lock();
+       /*
+        * cannot trust __rtnl_link_unregister() to unregister all
+        * devices, as each ->dellink call will remove two devices
+        * from the list at once.
+        */
+       list_for_each_entry_safe(priv, next, &veth_list, list)
+               veth_dellink(priv->dev);
+
+       __rtnl_link_unregister(&veth_link_ops);
+       rtnl_unlock();
+}
+
+module_init(veth_init);
+module_exit(veth_exit);
+
+MODULE_DESCRIPTION("Virtual Ethernet Tunnel");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS_RTNL_LINK(DRV_NAME);