text: /*
   * Copyright (c) 2007 Patrick McHardy <kaber@trash.net>
   *
   * This program is free software; you can redistribute it and/or
   * modify it under the terms of the GNU General Public License as
   * published by the Free Software Foundation; either version 2 of
   * the License, or (at your option) any later version.
   *
   * The code this is based on carried the following copyright notice:
   * ---
   * (C) Copyright 2001-2006
   * Alex Zeffertt, Cambridge Broadband Ltd, ajz@cambridgebroadband.com
   * Re-worked by Ben Greear <greearb@candelatech.com>
   * ---
   */
  #include <linux/kernel.h>
  #include <linux/types.h>
  #include <linux/module.h>
  #include <linux/init.h>
  #include <linux/errno.h>
  #include <linux/slab.h>
  #include <linux/string.h>
  #include <linux/rculist.h>
  #include <linux/notifier.h>
  #include <linux/netdevice.h>
  #include <linux/etherdevice.h>
  #include <linux/ethtool.h>
  #include <linux/if_arp.h>
  #include <linux/if_vlan.h>
  #include <linux/if_link.h>
  #include <linux/if_macvlan.h>
  #include <net/rtnetlink.h>
  #include <net/xfrm.h>
  
  #define MACVLAN_HASH_SIZE	(1 << BITS_PER_BYTE)
  
  struct macvlan_port {
  	struct net_device	*dev;
  	struct hlist_head	vlan_hash[MACVLAN_HASH_SIZE];
  	struct list_head	vlans;
  	struct rcu_head		rcu;
  	bool 			passthru;
  	int			count;
  };
  
  static void macvlan_port_destroy(struct net_device *dev);
  
  #define macvlan_port_get_rcu(dev) \
  	((struct macvlan_port *) rcu_dereference(dev->rx_handler_data))
  #define macvlan_port_get(dev) ((struct macvlan_port *) dev->rx_handler_data)
  #define macvlan_port_exists(dev) (dev->priv_flags & IFF_MACVLAN_PORT)
  
  static struct macvlan_dev *macvlan_hash_lookup(const struct macvlan_port *port,
  					       const unsigned char *addr)
  {
  	struct macvlan_dev *vlan;
  	struct hlist_node *n;
  
  	hlist_for_each_entry_rcu(vlan, n, &port->vlan_hash[addr[5]], hlist) {
  		if (ether_addr_equal_64bits(vlan->dev->dev_addr, addr))
  			return vlan;
  	}
  	return NULL;
  }
  
  static void macvlan_hash_add(struct macvlan_dev *vlan)
  {
  	struct macvlan_port *port = vlan->port;
  	const unsigned char *addr = vlan->dev->dev_addr;
  
  	hlist_add_head_rcu(&vlan->hlist, &port->vlan_hash[addr[5]]);
  }
  
  static void macvlan_hash_del(struct macvlan_dev *vlan, bool sync)
  {
  	hlist_del_rcu(&vlan->hlist);
  	if (sync)
  		synchronize_rcu();
  }
  
  static void macvlan_hash_change_addr(struct macvlan_dev *vlan,
  					const unsigned char *addr)
  {
  	macvlan_hash_del(vlan, true);
  	/* Now that we are unhashed it is safe to change the device
  	 * address without confusing packet delivery.
  	 */
  	memcpy(vlan->dev->dev_addr, addr, ETH_ALEN);
  	macvlan_hash_add(vlan);
  }
  
  static int macvlan_addr_busy(const struct macvlan_port *port,
  				const unsigned char *addr)
  {
  	/* Test to see if the specified multicast address is
  	 * currently in use by the underlying device or
  	 * another macvlan.
  	 */
  	if (ether_addr_equal_64bits(port->dev->dev_addr, addr))
  		return 1;
  
  	if (macvlan_hash_lookup(port, addr))
  		return 1;
  
  	return 0;
  }
  
  
  static int macvlan_broadcast_one(struct sk_buff *skb,
  				 const struct macvlan_dev *vlan,
  				 const struct ethhdr *eth, bool local)
  {
  	struct net_device *dev = vlan->dev;
  	if (!skb)
  		return NET_RX_DROP;
  
  	if (local)
  		return vlan->forward(dev, skb);
  
  	skb->dev = dev;
  	if (ether_addr_equal_64bits(eth->h_dest, dev->broadcast))
  		skb->pkt_type = PACKET_BROADCAST;
  	else
  		skb->pkt_type = PACKET_MULTICAST;
  
  	return vlan->receive(skb);
  }
  
  static void macvlan_broadcast(struct sk_buff *skb,
  			      const struct macvlan_port *port,
  			      struct net_device *src,
  			      enum macvlan_mode mode)
  {
  	const struct ethhdr *eth = eth_hdr(skb);
  	const struct macvlan_dev *vlan;
  	struct hlist_node *n;
  	struct sk_buff *nskb;
  	unsigned int i;
  	int err;
  
  	if (skb->protocol == htons(ETH_P_PAUSE))
  		return;
  
  	for (i = 0; i < MACVLAN_HASH_SIZE; i++) {
  		hlist_for_each_entry_rcu(vlan, n, &port->vlan_hash[i], hlist) {
  			if (vlan->dev == src || !(vlan->mode & mode))
  				continue;
  
  			nskb = skb_clone(skb, GFP_ATOMIC);
  			err = macvlan_broadcast_one(nskb, vlan, eth,
  					 mode == MACVLAN_MODE_BRIDGE);
  			macvlan_count_rx(vlan, skb->len + ETH_HLEN,
  					 err == NET_RX_SUCCESS, 1);
  		}
  	}
  }
  
  /* called under rcu_read_lock() from netif_receive_skb */
  static rx_handler_result_t macvlan_handle_frame(struct sk_buff **pskb)
  {
  	struct macvlan_port *port;
  	struct sk_buff *skb = *pskb;
  	const struct ethhdr *eth = eth_hdr(skb);
  	const struct macvlan_dev *vlan;
  	const struct macvlan_dev *src;
  	struct net_device *dev;
  	unsigned int len = 0;
  	int ret = NET_RX_DROP;
  
  	port = macvlan_port_get_rcu(skb->dev);
  	if (is_multicast_ether_addr(eth->h_dest)) {
  		skb = ip_check_defrag(skb, IP_DEFRAG_MACVLAN);
  		if (!skb)
  			return RX_HANDLER_CONSUMED;
  		eth = eth_hdr(skb);
  		src = macvlan_hash_lookup(port, eth->h_source);
  		if (!src)
  			/* frame comes from an external address */
  			macvlan_broadcast(skb, port, NULL,
  					  MACVLAN_MODE_PRIVATE |
  					  MACVLAN_MODE_VEPA    |
  					  MACVLAN_MODE_PASSTHRU|
  					  MACVLAN_MODE_BRIDGE);
  		else if (src->mode == MACVLAN_MODE_VEPA)
  			/* flood to everyone except source */
  			macvlan_broadcast(skb, port, src->dev,
  					  MACVLAN_MODE_VEPA |
  					  MACVLAN_MODE_BRIDGE);
  		else if (src->mode == MACVLAN_MODE_BRIDGE)
  			/*
  			 * flood only to VEPA ports, bridge ports
  			 * already saw the frame on the way out.
  			 */
  			macvlan_broadcast(skb, port, src->dev,
  					  MACVLAN_MODE_VEPA);
  		else {
  			/* forward to original port. */
  			vlan = src;
  			ret = macvlan_broadcast_one(skb, vlan, eth, 0);
  			goto out;
  		}
  
  		return RX_HANDLER_PASS;
  	}
  
  	if (port->passthru)
  		vlan = list_first_entry(&port->vlans, struct macvlan_dev, list);
  	else
  		vlan = macvlan_hash_lookup(port, eth->h_dest);
  	if (vlan == NULL)
  		return RX_HANDLER_PASS;
  
  	dev = vlan->dev;
  	if (unlikely(!(dev->flags & IFF_UP))) {
  		kfree_skb(skb);
  		return RX_HANDLER_CONSUMED;
  	}
  	len = skb->len + ETH_HLEN;
  	skb = skb_share_check(skb, GFP_ATOMIC);
  	if (!skb)
  		goto out;
  
  	skb->dev = dev;
  	skb->pkt_type = PACKET_HOST;
  
  	ret = vlan->receive(skb);
  
  out:
  	macvlan_count_rx(vlan, len, ret == NET_RX_SUCCESS, 0);
  	return RX_HANDLER_CONSUMED;
  }
  
  static int macvlan_queue_xmit(struct sk_buff *skb, struct net_device *dev)
  {
  	const struct macvlan_dev *vlan = netdev_priv(dev);
  	const struct macvlan_port *port = vlan->port;
  	const struct macvlan_dev *dest;
  	__u8 ip_summed = skb->ip_summed;
  
  	if (vlan->mode == MACVLAN_MODE_BRIDGE) {
  		const struct ethhdr *eth = (void *)skb->data;
  		skb->ip_summed = CHECKSUM_UNNECESSARY;
  
  		/* send to other bridge ports directly */
  		if (is_multicast_ether_addr(eth->h_dest)) {
  			macvlan_broadcast(skb, port, dev, MACVLAN_MODE_BRIDGE);
  			goto xmit_world;
  		}
  
  		dest = macvlan_hash_lookup(port, eth->h_dest);
  		if (dest && dest->mode == MACVLAN_MODE_BRIDGE) {
  			/* send to lowerdev first for its network taps */
  			dev_forward_skb(vlan->lowerdev, skb);
  
  			return NET_XMIT_SUCCESS;
  		}
  	}
  
  xmit_world:
  	skb->ip_summed = ip_summed;
  	skb->dev = vlan->lowerdev;
  	return dev_queue_xmit(skb);
  }
  
  netdev_tx_t macvlan_start_xmit(struct sk_buff *skb,
  			       struct net_device *dev)
  {
  	unsigned int len = skb->len;
  	int ret;
  	const struct macvlan_dev *vlan = netdev_priv(dev);
  
  	ret = macvlan_queue_xmit(skb, dev);
  	if (likely(ret == NET_XMIT_SUCCESS || ret == NET_XMIT_CN)) {
  		struct macvlan_pcpu_stats *pcpu_stats;
  
  		pcpu_stats = this_cpu_ptr(vlan->pcpu_stats);
  		u64_stats_update_begin(&pcpu_stats->syncp);
  		pcpu_stats->tx_packets++;
  		pcpu_stats->tx_bytes += len;
  		u64_stats_update_end(&pcpu_stats->syncp);
  	} else {
  		this_cpu_inc(vlan->pcpu_stats->tx_dropped);
  	}
  	return ret;
  }
  EXPORT_SYMBOL_GPL(macvlan_start_xmit);
  
  static int macvlan_hard_header(struct sk_buff *skb, struct net_device *dev,
  			       unsigned short type, const void *daddr,
  			       const void *saddr, unsigned len)
  {
  	const struct macvlan_dev *vlan = netdev_priv(dev);
  	struct net_device *lowerdev = vlan->lowerdev;
  
  	return dev_hard_header(skb, lowerdev, type, daddr,
  			       saddr ? : dev->dev_addr, len);
  }
  
  static const struct header_ops macvlan_hard_header_ops = {
  	.create  	= macvlan_hard_header,
  	.rebuild	= eth_rebuild_header,
  	.parse		= eth_header_parse,
  	.cache		= eth_header_cache,
  	.cache_update	= eth_header_cache_update,
  };
  
  static int macvlan_open(struct net_device *dev)
  {
  	struct macvlan_dev *vlan = netdev_priv(dev);
  	struct net_device *lowerdev = vlan->lowerdev;
  	int err;
  
  	if (vlan->port->passthru) {
  		if (!(vlan->flags & MACVLAN_FLAG_NOPROMISC))
  			dev_set_promiscuity(lowerdev, 1);
  		goto hash_add;
  	}
  
  	err = -EBUSY;
  	if (macvlan_addr_busy(vlan->port, dev->dev_addr))
  		goto out;
  
  	err = dev_uc_add(lowerdev, dev->dev_addr);
  	if (err < 0)
  		goto out;
  	if (dev->flags & IFF_ALLMULTI) {
  		err = dev_set_allmulti(lowerdev, 1);
  		if (err < 0)
  			goto del_unicast;
  	}
  
  hash_add:
  	macvlan_hash_add(vlan);
  	return 0;
  
  del_unicast:
  	dev_uc_del(lowerdev, dev->dev_addr);
  out:
  	return err;
  }
  
  static int macvlan_stop(struct net_device *dev)
  {
  	struct macvlan_dev *vlan = netdev_priv(dev);
  	struct net_device *lowerdev = vlan->lowerdev;
  
  	dev_uc_unsync(lowerdev, dev);
  	dev_mc_unsync(lowerdev, dev);
  
  	if (vlan->port->passthru) {
  		if (!(vlan->flags & MACVLAN_FLAG_NOPROMISC))
  			dev_set_promiscuity(lowerdev, -1);
  		goto hash_del;
  	}
  
  	if (dev->flags & IFF_ALLMULTI)
  		dev_set_allmulti(lowerdev, -1);
  
  	dev_uc_del(lowerdev, dev->dev_addr);
  
  hash_del:
  	macvlan_hash_del(vlan, !dev->dismantle);
  	return 0;
  }
  
  static int macvlan_set_mac_address(struct net_device *dev, void *p)
  {
  	struct macvlan_dev *vlan = netdev_priv(dev);
  	struct net_device *lowerdev = vlan->lowerdev;
  	struct sockaddr *addr = p;
  	int err;
  
  	if (!is_valid_ether_addr(addr->sa_data))
  		return -EADDRNOTAVAIL;
  
  	if (!(dev->flags & IFF_UP)) {
  		/* Just copy in the new address */
  		dev->addr_assign_type &= ~NET_ADDR_RANDOM;
  		memcpy(dev->dev_addr, addr->sa_data, ETH_ALEN);
  	} else {
  		/* Rehash and update the device filters */
  		if (macvlan_addr_busy(vlan->port, addr->sa_data))
  			return -EBUSY;
  
  		err = dev_uc_add(lowerdev, addr->sa_data);
  		if (err)
  			return err;
  
  		dev_uc_del(lowerdev, dev->dev_addr);
  
  		macvlan_hash_change_addr(vlan, addr->sa_data);
  	}
  	return 0;
  }
  
  static void macvlan_change_rx_flags(struct net_device *dev, int change)
  {
  	struct macvlan_dev *vlan = netdev_priv(dev);
  	struct net_device *lowerdev = vlan->lowerdev;
  
  	if (change & IFF_ALLMULTI)
  		dev_set_allmulti(lowerdev, dev->flags & IFF_ALLMULTI ? 1 : -1);
  }
  
  static void macvlan_set_mac_lists(struct net_device *dev)
  {
  	struct macvlan_dev *vlan = netdev_priv(dev);
  
  	dev_uc_sync(vlan->lowerdev, dev);
  	dev_mc_sync(vlan->lowerdev, dev);
  }
  
  static int macvlan_change_mtu(struct net_device *dev, int new_mtu)
  {
  	struct macvlan_dev *vlan = netdev_priv(dev);
  
  	if (new_mtu < 68 || vlan->lowerdev->mtu < new_mtu)
  		return -EINVAL;
  	dev->mtu = new_mtu;
  	return 0;
  }
  
  /*
   * macvlan network devices have devices nesting below it and are a special
   * "super class" of normal network devices; split their locks off into a
   * separate class since they always nest.
   */
  static struct lock_class_key macvlan_netdev_xmit_lock_key;
  static struct lock_class_key macvlan_netdev_addr_lock_key;
  
  #define MACVLAN_FEATURES \
  	(NETIF_F_SG | NETIF_F_ALL_CSUM | NETIF_F_HIGHDMA | NETIF_F_FRAGLIST | \
  	 NETIF_F_GSO | NETIF_F_TSO | NETIF_F_UFO | NETIF_F_GSO_ROBUST | \
  	 NETIF_F_TSO_ECN | NETIF_F_TSO6 | NETIF_F_GRO | NETIF_F_RXCSUM | \
  	 NETIF_F_HW_VLAN_FILTER)
  
  #define MACVLAN_STATE_MASK \
  	((1<<__LINK_STATE_NOCARRIER) | (1<<__LINK_STATE_DORMANT))
  
  static void macvlan_set_lockdep_class_one(struct net_device *dev,
  					  struct netdev_queue *txq,
  					  void *_unused)
  {
  	lockdep_set_class(&txq->_xmit_lock,
  			  &macvlan_netdev_xmit_lock_key);
  }
  
  static void macvlan_set_lockdep_class(struct net_device *dev)
  {
  	lockdep_set_class(&dev->addr_list_lock,
  			  &macvlan_netdev_addr_lock_key);
  	netdev_for_each_tx_queue(dev, macvlan_set_lockdep_class_one, NULL);
  }
  
  static int macvlan_init(struct net_device *dev)
  {
  	struct macvlan_dev *vlan = netdev_priv(dev);
  	const struct net_device *lowerdev = vlan->lowerdev;
  
  	dev->state		= (dev->state & ~MACVLAN_STATE_MASK) |
  				  (lowerdev->state & MACVLAN_STATE_MASK);
  	dev->features 		= lowerdev->features & MACVLAN_FEATURES;
  	dev->features		|= NETIF_F_LLTX;
  	dev->gso_max_size	= lowerdev->gso_max_size;
  	dev->iflink		= lowerdev->ifindex;
  	dev->hard_header_len	= lowerdev->hard_header_len;
  
  	macvlan_set_lockdep_class(dev);
  
  	vlan->pcpu_stats = alloc_percpu(struct macvlan_pcpu_stats);
  	if (!vlan->pcpu_stats)
  		return -ENOMEM;
  
  	return 0;
  }
  
  static void macvlan_uninit(struct net_device *dev)
  {
  	struct macvlan_dev *vlan = netdev_priv(dev);
  	struct macvlan_port *port = vlan->port;
  
  	free_percpu(vlan->pcpu_stats);
  
  	port->count -= 1;
  	if (!port->count)
  		macvlan_port_destroy(port->dev);
  }
  
  static struct rtnl_link_stats64 *macvlan_dev_get_stats64(struct net_device *dev,
  							 struct rtnl_link_stats64 *stats)
  {
  	struct macvlan_dev *vlan = netdev_priv(dev);
  
  	if (vlan->pcpu_stats) {
  		struct macvlan_pcpu_stats *p;
  		u64 rx_packets, rx_bytes, rx_multicast, tx_packets, tx_bytes;
  		u32 rx_errors = 0, tx_dropped = 0;
  		unsigned int start;
  		int i;
  
  		for_each_possible_cpu(i) {
  			p = per_cpu_ptr(vlan->pcpu_stats, i);
  			do {
  				start = u64_stats_fetch_begin_bh(&p->syncp);
  				rx_packets	= p->rx_packets;
  				rx_bytes	= p->rx_bytes;
  				rx_multicast	= p->rx_multicast;
  				tx_packets	= p->tx_packets;
  				tx_bytes	= p->tx_bytes;
  			} while (u64_stats_fetch_retry_bh(&p->syncp, start));
  
  			stats->rx_packets	+= rx_packets;
  			stats->rx_bytes		+= rx_bytes;
  			stats->multicast	+= rx_multicast;
  			stats->tx_packets	+= tx_packets;
  			stats->tx_bytes		+= tx_bytes;
  			/* rx_errors & tx_dropped are u32, updated
  			 * without syncp protection.
  			 */
  			rx_errors	+= p->rx_errors;
  			tx_dropped	+= p->tx_dropped;
  		}
  		stats->rx_errors	= rx_errors;
  		stats->rx_dropped	= rx_errors;
  		stats->tx_dropped	= tx_dropped;
  	}
  	return stats;
  }
  
  static int macvlan_vlan_rx_add_vid(struct net_device *dev,
  				    unsigned short vid)
  {
  	struct macvlan_dev *vlan = netdev_priv(dev);
  	struct net_device *lowerdev = vlan->lowerdev;
  
  	return vlan_vid_add(lowerdev, vid);
  }
  
  static int macvlan_vlan_rx_kill_vid(struct net_device *dev,
  				     unsigned short vid)
  {
  	struct macvlan_dev *vlan = netdev_priv(dev);
  	struct net_device *lowerdev = vlan->lowerdev;
  
  	vlan_vid_del(lowerdev, vid);
  	return 0;
  }
  
  static int macvlan_fdb_add(struct ndmsg *ndm,
  			   struct net_device *dev,
  			   unsigned char *addr,
  			   u16 flags)
  {
  	struct macvlan_dev *vlan = netdev_priv(dev);
  	int err = -EINVAL;
  
  	if (!vlan->port->passthru)
  		return -EOPNOTSUPP;
  
  	if (is_unicast_ether_addr(addr))
  		err = dev_uc_add_excl(dev, addr);
  	else if (is_multicast_ether_addr(addr))
  		err = dev_mc_add_excl(dev, addr);
  
  	return err;
  }
  
  static int macvlan_fdb_del(struct ndmsg *ndm,
  			   struct net_device *dev,
  			   unsigned char *addr)
  {
  	struct macvlan_dev *vlan = netdev_priv(dev);
  	int err = -EINVAL;
  
  	if (!vlan->port->passthru)
  		return -EOPNOTSUPP;
  
  	if (is_unicast_ether_addr(addr))
  		err = dev_uc_del(dev, addr);
  	else if (is_multicast_ether_addr(addr))
  		err = dev_mc_del(dev, addr);
  
  	return err;
  }
  
  static void macvlan_ethtool_get_drvinfo(struct net_device *dev,
  					struct ethtool_drvinfo *drvinfo)
  {
  	snprintf(drvinfo->driver, 32, "macvlan");
  	snprintf(drvinfo->version, 32, "0.1");
  }
  
  static int macvlan_ethtool_get_settings(struct net_device *dev,
  					struct ethtool_cmd *cmd)
  {
  	const struct macvlan_dev *vlan = netdev_priv(dev);
  
  	return __ethtool_get_settings(vlan->lowerdev, cmd);
  }
  
  static const struct ethtool_ops macvlan_ethtool_ops = {
  	.get_link		= ethtool_op_get_link,
  	.get_settings		= macvlan_ethtool_get_settings,
  	.get_drvinfo		= macvlan_ethtool_get_drvinfo,
  };
  
  static const struct net_device_ops macvlan_netdev_ops = {
  	.ndo_init		= macvlan_init,
  	.ndo_uninit		= macvlan_uninit,
  	.ndo_open		= macvlan_open,
  	.ndo_stop		= macvlan_stop,
  	.ndo_start_xmit		= macvlan_start_xmit,
  	.ndo_change_mtu		= macvlan_change_mtu,
  	.ndo_change_rx_flags	= macvlan_change_rx_flags,
  	.ndo_set_mac_address	= macvlan_set_mac_address,
  	.ndo_set_rx_mode	= macvlan_set_mac_lists,
  	.ndo_get_stats64	= macvlan_dev_get_stats64,
  	.ndo_validate_addr	= eth_validate_addr,
  	.ndo_vlan_rx_add_vid	= macvlan_vlan_rx_add_vid,
  	.ndo_vlan_rx_kill_vid	= macvlan_vlan_rx_kill_vid,
  	.ndo_fdb_add		= macvlan_fdb_add,
  	.ndo_fdb_del		= macvlan_fdb_del,
  	.ndo_fdb_dump		= ndo_dflt_fdb_dump,
  };
  
  void macvlan_common_setup(struct net_device *dev)
  {
  	ether_setup(dev);
  
  	dev->priv_flags	       &= ~(IFF_XMIT_DST_RELEASE | IFF_TX_SKB_SHARING);
  	dev->netdev_ops		= &macvlan_netdev_ops;
  	dev->destructor		= free_netdev;
  	dev->header_ops		= &macvlan_hard_header_ops,
  	dev->ethtool_ops	= &macvlan_ethtool_ops;
  }
  EXPORT_SYMBOL_GPL(macvlan_common_setup);
  
  static void macvlan_setup(struct net_device *dev)
  {
  	macvlan_common_setup(dev);
  	dev->tx_queue_len	= 0;
  }
  
  static int macvlan_port_create(struct net_device *dev)
  {
  	struct macvlan_port *port;
  	unsigned int i;
  	int err;
  
  	if (dev->type != ARPHRD_ETHER || dev->flags & IFF_LOOPBACK)
  		return -EINVAL;
  
  	port = kzalloc(sizeof(*port), GFP_KERNEL);
  	if (port == NULL)
  		return -ENOMEM;
  
  	port->passthru = false;
  	port->dev = dev;
  	INIT_LIST_HEAD(&port->vlans);
  	for (i = 0; i < MACVLAN_HASH_SIZE; i++)
  		INIT_HLIST_HEAD(&port->vlan_hash[i]);
  
  	err = netdev_rx_handler_register(dev, macvlan_handle_frame, port);
  	if (err)
  		kfree(port);
  	else
  		dev->priv_flags |= IFF_MACVLAN_PORT;
  	return err;
  }
  
  static void macvlan_port_destroy(struct net_device *dev)
  {
  	struct macvlan_port *port = macvlan_port_get(dev);
  
  	dev->priv_flags &= ~IFF_MACVLAN_PORT;
  	netdev_rx_handler_unregister(dev);
  	kfree_rcu(port, rcu);
  }
  
  static int macvlan_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;
  	}
  
  	if (data && data[IFLA_MACVLAN_MODE]) {
  		switch (nla_get_u32(data[IFLA_MACVLAN_MODE])) {
  		case MACVLAN_MODE_PRIVATE:
  		case MACVLAN_MODE_VEPA:
  		case MACVLAN_MODE_BRIDGE:
  		case MACVLAN_MODE_PASSTHRU:
  			break;
  		default:
  			return -EINVAL;
  		}
  	}
  	return 0;
  }
  
  int macvlan_common_newlink(struct net *src_net, struct net_device *dev,
  			   struct nlattr *tb[], struct nlattr *data[],
  			   int (*receive)(struct sk_buff *skb),
  			   int (*forward)(struct net_device *dev,
  					  struct sk_buff *skb))
  {
  	struct macvlan_dev *vlan = netdev_priv(dev);
  	struct macvlan_port *port;
  	struct net_device *lowerdev;
  	int err;
  
  	if (!tb[IFLA_LINK])
  		return -EINVAL;
  
  	lowerdev = __dev_get_by_index(src_net, nla_get_u32(tb[IFLA_LINK]));
  	if (lowerdev == NULL)
  		return -ENODEV;
  
  	/* When creating macvlans on top of other macvlans - use
  	 * the real device as the lowerdev.
  	 */
  	if (lowerdev->rtnl_link_ops == dev->rtnl_link_ops) {
  		struct macvlan_dev *lowervlan = netdev_priv(lowerdev);
  		lowerdev = lowervlan->lowerdev;
  	}
  
  	if (!tb[IFLA_MTU])
  		dev->mtu = lowerdev->mtu;
  	else if (dev->mtu > lowerdev->mtu)
  		return -EINVAL;
  
  	if (!tb[IFLA_ADDRESS])
  		eth_hw_addr_random(dev);
  
  	if (!macvlan_port_exists(lowerdev)) {
  		err = macvlan_port_create(lowerdev);
  		if (err < 0)
  			return err;
  	}
  	port = macvlan_port_get(lowerdev);
  
  	/* Only 1 macvlan device can be created in passthru mode */
  	if (port->passthru)
  		return -EINVAL;
  
  	vlan->lowerdev = lowerdev;
  	vlan->dev      = dev;
  	vlan->port     = port;
  	vlan->receive  = receive;
  	vlan->forward  = forward;
  
  	vlan->mode     = MACVLAN_MODE_VEPA;
  	if (data && data[IFLA_MACVLAN_MODE])
  		vlan->mode = nla_get_u32(data[IFLA_MACVLAN_MODE]);
  
  	if (data && data[IFLA_MACVLAN_FLAGS])
  		vlan->flags = nla_get_u16(data[IFLA_MACVLAN_FLAGS]);
  
  	if (vlan->mode == MACVLAN_MODE_PASSTHRU) {
  		if (port->count)
  			return -EINVAL;
  		port->passthru = true;
  		memcpy(dev->dev_addr, lowerdev->dev_addr, ETH_ALEN);
  	}
  
  	port->count += 1;
  	err = register_netdevice(dev);
  	if (err < 0)
  		goto destroy_port;
  
  	list_add_tail(&vlan->list, &port->vlans);
  	netif_stacked_transfer_operstate(lowerdev, dev);
  
  	return 0;
  
  destroy_port:
  	port->count -= 1;
  	if (!port->count)
  		macvlan_port_destroy(lowerdev);
  
  	return err;
  }
  EXPORT_SYMBOL_GPL(macvlan_common_newlink);
  
  static int macvlan_newlink(struct net *src_net, struct net_device *dev,
  			   struct nlattr *tb[], struct nlattr *data[])
  {
  	return macvlan_common_newlink(src_net, dev, tb, data,
  				      netif_rx,
  				      dev_forward_skb);
  }
  
  void macvlan_dellink(struct net_device *dev, struct list_head *head)
  {
  	struct macvlan_dev *vlan = netdev_priv(dev);
  
  	list_del(&vlan->list);
  	unregister_netdevice_queue(dev, head);
  }
  EXPORT_SYMBOL_GPL(macvlan_dellink);
  
  static int macvlan_changelink(struct net_device *dev,
  		struct nlattr *tb[], struct nlattr *data[])
  {
  	struct macvlan_dev *vlan = netdev_priv(dev);
  	if (data && data[IFLA_MACVLAN_MODE])
  		vlan->mode = nla_get_u32(data[IFLA_MACVLAN_MODE]);
  	if (data && data[IFLA_MACVLAN_FLAGS]) {
  		__u16 flags = nla_get_u16(data[IFLA_MACVLAN_FLAGS]);
  		bool promisc = (flags ^ vlan->flags) & MACVLAN_FLAG_NOPROMISC;
  
  		if (promisc && (flags & MACVLAN_FLAG_NOPROMISC))
  			dev_set_promiscuity(vlan->lowerdev, -1);
  		else if (promisc && !(flags & MACVLAN_FLAG_NOPROMISC))
  			dev_set_promiscuity(vlan->lowerdev, 1);
  		vlan->flags = flags;
  	}
  	return 0;
  }
  
  static size_t macvlan_get_size(const struct net_device *dev)
  {
  	return nla_total_size(4);
  }
  
  static int macvlan_fill_info(struct sk_buff *skb,
  				const struct net_device *dev)
  {
  	struct macvlan_dev *vlan = netdev_priv(dev);
  
  	if (nla_put_u32(skb, IFLA_MACVLAN_MODE, vlan->mode))
  		goto nla_put_failure;
  	if (nla_put_u16(skb, IFLA_MACVLAN_FLAGS, vlan->flags))
  		goto nla_put_failure;
  	return 0;
  
  nla_put_failure:
  	return -EMSGSIZE;
  }
  
  static const struct nla_policy macvlan_policy[IFLA_MACVLAN_MAX + 1] = {
  	[IFLA_MACVLAN_MODE]  = { .type = NLA_U32 },
  	[IFLA_MACVLAN_FLAGS] = { .type = NLA_U16 },
  };
  
  int macvlan_link_register(struct rtnl_link_ops *ops)
  {
  	/* common fields */
  	ops->priv_size		= sizeof(struct macvlan_dev);
  	ops->validate		= macvlan_validate;
  	ops->maxtype		= IFLA_MACVLAN_MAX;
  	ops->policy		= macvlan_policy;
  	ops->changelink		= macvlan_changelink;
  	ops->get_size		= macvlan_get_size;
  	ops->fill_info		= macvlan_fill_info;
  
  	return rtnl_link_register(ops);
  };
  EXPORT_SYMBOL_GPL(macvlan_link_register);
  
  static struct rtnl_link_ops macvlan_link_ops = {
  	.kind		= "macvlan",
  	.setup		= macvlan_setup,
  	.newlink	= macvlan_newlink,
  	.dellink	= macvlan_dellink,
  };
  
  static int macvlan_device_event(struct notifier_block *unused,
  				unsigned long event, void *ptr)
  {
  	struct net_device *dev = ptr;
  	struct macvlan_dev *vlan, *next;
  	struct macvlan_port *port;
  	LIST_HEAD(list_kill);
  
  	if (!macvlan_port_exists(dev))
  		return NOTIFY_DONE;
  
  	port = macvlan_port_get(dev);
  
  	switch (event) {
  	case NETDEV_CHANGE:
  		list_for_each_entry(vlan, &port->vlans, list)
  			netif_stacked_transfer_operstate(vlan->lowerdev,
  							 vlan->dev);
  		break;
  	case NETDEV_FEAT_CHANGE:
  		list_for_each_entry(vlan, &port->vlans, list) {
  			vlan->dev->features = dev->features & MACVLAN_FEATURES;
  			vlan->dev->gso_max_size = dev->gso_max_size;
  			netdev_features_change(vlan->dev);
  		}
  		break;
  	case NETDEV_UNREGISTER:
  		/* twiddle thumbs on netns device moves */
  		if (dev->reg_state != NETREG_UNREGISTERING)
  			break;
  
  		list_for_each_entry_safe(vlan, next, &port->vlans, list)
  			vlan->dev->rtnl_link_ops->dellink(vlan->dev, &list_kill);
  		unregister_netdevice_many(&list_kill);
  		list_del(&list_kill);
  		break;
  	case NETDEV_PRE_TYPE_CHANGE:
  		/* Forbid underlaying device to change its type. */
  		return NOTIFY_BAD;
  	}
  	return NOTIFY_DONE;
  }
  
  static struct notifier_block macvlan_notifier_block __read_mostly = {
  	.notifier_call	= macvlan_device_event,
  };
  
  static int __init macvlan_init_module(void)
  {
  	int err;
  
  	register_netdevice_notifier(&macvlan_notifier_block);
  
  	err = macvlan_link_register(&macvlan_link_ops);
  	if (err < 0)
  		goto err1;
  	return 0;
  err1:
  	unregister_netdevice_notifier(&macvlan_notifier_block);
  	return err;
  }
  
  static void __exit macvlan_cleanup_module(void)
  {
  	rtnl_link_unregister(&macvlan_link_ops);
  	unregister_netdevice_notifier(&macvlan_notifier_block);
  }
  
  module_init(macvlan_init_module);
  module_exit(macvlan_cleanup_module);
  
  MODULE_LICENSE("GPL");
  MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
  MODULE_DESCRIPTION("Driver for MAC address based VLANs");
  MODULE_ALIAS_RTNL_LINK("macvlan");
  