// SPDX-License-Identifier: GPL-2.0-or-later

  /*
   * vrf.c: device driver to encapsulate a VRF space
   *
   * Copyright (c) 2015 Cumulus Networks. All rights reserved.
   * Copyright (c) 2015 Shrijeet Mukherjee <shm@cumulusnetworks.com>
   * Copyright (c) 2015 David Ahern <dsa@cumulusnetworks.com>
   *
   * Based on dummy, team and ipvlan drivers

   */
  
  #include <linux/module.h>
  #include <linux/kernel.h>
  #include <linux/netdevice.h>
  #include <linux/etherdevice.h>
  #include <linux/ip.h>
  #include <linux/init.h>
  #include <linux/moduleparam.h>
  #include <linux/netfilter.h>
  #include <linux/rtnetlink.h>
  #include <net/rtnetlink.h>
  #include <linux/u64_stats_sync.h>
  #include <linux/hashtable.h>
  
  #include <linux/inetdevice.h>

  #include <net/arp.h>

  #include <net/ip.h>
  #include <net/ip_fib.h>

  #include <net/ip6_fib.h>

  #include <net/ip6_route.h>

  #include <net/route.h>
  #include <net/addrconf.h>

  #include <net/l3mdev.h>

  #include <net/fib_rules.h>

  #include <net/netns/generic.h>

  
  #define DRV_NAME	"vrf"
  #define DRV_VERSION	"1.0"

  #define FIB_RULE_PREF  1000       /* default preference for FIB rules */

  
  static unsigned int vrf_net_id;

  struct net_vrf {

  	struct rtable __rcu	*rth;
  	struct rt6_info	__rcu	*rt6;

  #if IS_ENABLED(CONFIG_IPV6)
  	struct fib6_table	*fib6_table;
  #endif

  	u32                     tb_id;
  };

  struct pcpu_dstats {
  	u64			tx_pkts;
  	u64			tx_bytes;
  	u64			tx_drps;
  	u64			rx_pkts;
  	u64			rx_bytes;

  	u64			rx_drps;

  	struct u64_stats_sync	syncp;
  };

  static void vrf_rx_stats(struct net_device *dev, int len)
  {
  	struct pcpu_dstats *dstats = this_cpu_ptr(dev->dstats);
  
  	u64_stats_update_begin(&dstats->syncp);
  	dstats->rx_pkts++;
  	dstats->rx_bytes += len;
  	u64_stats_update_end(&dstats->syncp);
  }

  static void vrf_tx_error(struct net_device *vrf_dev, struct sk_buff *skb)
  {
  	vrf_dev->stats.tx_errors++;
  	kfree_skb(skb);
  }

  static void vrf_get_stats64(struct net_device *dev,
  			    struct rtnl_link_stats64 *stats)

  {
  	int i;
  
  	for_each_possible_cpu(i) {
  		const struct pcpu_dstats *dstats;
  		u64 tbytes, tpkts, tdrops, rbytes, rpkts;
  		unsigned int start;
  
  		dstats = per_cpu_ptr(dev->dstats, i);
  		do {
  			start = u64_stats_fetch_begin_irq(&dstats->syncp);
  			tbytes = dstats->tx_bytes;
  			tpkts = dstats->tx_pkts;
  			tdrops = dstats->tx_drps;
  			rbytes = dstats->rx_bytes;
  			rpkts = dstats->rx_pkts;
  		} while (u64_stats_fetch_retry_irq(&dstats->syncp, start));
  		stats->tx_bytes += tbytes;
  		stats->tx_packets += tpkts;
  		stats->tx_dropped += tdrops;
  		stats->rx_bytes += rbytes;
  		stats->rx_packets += rpkts;
  	}

  }

  /* by default VRF devices do not have a qdisc and are expected
   * to be created with only a single queue.
   */
  static bool qdisc_tx_is_default(const struct net_device *dev)
  {
  	struct netdev_queue *txq;
  	struct Qdisc *qdisc;
  
  	if (dev->num_tx_queues > 1)
  		return false;
  
  	txq = netdev_get_tx_queue(dev, 0);
  	qdisc = rcu_access_pointer(txq->qdisc);
  
  	return !qdisc->enqueue;
  }

  /* Local traffic destined to local address. Reinsert the packet to rx
   * path, similar to loopback handling.
   */
  static int vrf_local_xmit(struct sk_buff *skb, struct net_device *dev,
  			  struct dst_entry *dst)
  {
  	int len = skb->len;
  
  	skb_orphan(skb);
  
  	skb_dst_set(skb, dst);

  
  	/* set pkt_type to avoid skb hitting packet taps twice -
  	 * once on Tx and again in Rx processing
  	 */
  	skb->pkt_type = PACKET_LOOPBACK;
  
  	skb->protocol = eth_type_trans(skb, dev);
  
  	if (likely(netif_rx(skb) == NET_RX_SUCCESS))
  		vrf_rx_stats(dev, len);
  	else
  		this_cpu_inc(dev->dstats->rx_drps);
  
  	return NETDEV_TX_OK;
  }

  #if IS_ENABLED(CONFIG_IPV6)

  static int vrf_ip6_local_out(struct net *net, struct sock *sk,
  			     struct sk_buff *skb)
  {
  	int err;
  
  	err = nf_hook(NFPROTO_IPV6, NF_INET_LOCAL_OUT, net,
  		      sk, skb, NULL, skb_dst(skb)->dev, dst_output);
  
  	if (likely(err == 1))
  		err = dst_output(net, sk, skb);
  
  	return err;
  }

  static netdev_tx_t vrf_process_v6_outbound(struct sk_buff *skb,
  					   struct net_device *dev)
  {

  	const struct ipv6hdr *iph;

  	struct net *net = dev_net(skb->dev);

  	struct flowi6 fl6;

  	int ret = NET_XMIT_DROP;
  	struct dst_entry *dst;
  	struct dst_entry *dst_null = &net->ipv6.ip6_null_entry->dst;

  	if (!pskb_may_pull(skb, ETH_HLEN + sizeof(struct ipv6hdr)))
  		goto err;
  
  	iph = ipv6_hdr(skb);
  
  	memset(&fl6, 0, sizeof(fl6));
  	/* needed to match OIF rule */
  	fl6.flowi6_oif = dev->ifindex;
  	fl6.flowi6_iif = LOOPBACK_IFINDEX;
  	fl6.daddr = iph->daddr;
  	fl6.saddr = iph->saddr;
  	fl6.flowlabel = ip6_flowinfo(iph);
  	fl6.flowi6_mark = skb->mark;
  	fl6.flowi6_proto = iph->nexthdr;
  	fl6.flowi6_flags = FLOWI_FLAG_SKIP_NH_OIF;

  	dst = ip6_route_output(net, NULL, &fl6);
  	if (dst == dst_null)
  		goto err;
  
  	skb_dst_drop(skb);

  
  	/* if dst.dev is loopback or the VRF device again this is locally
  	 * originated traffic destined to a local address. Short circuit

  	 * to Rx path

  	 */

  	if (dst->dev == dev)
  		return vrf_local_xmit(skb, dev, dst);

  	skb_dst_set(skb, dst);

  	/* strip the ethernet header added for pass through VRF device */
  	__skb_pull(skb, skb_network_offset(skb));

  	ret = vrf_ip6_local_out(net, skb->sk, skb);

  	if (unlikely(net_xmit_eval(ret)))
  		dev->stats.tx_errors++;
  	else
  		ret = NET_XMIT_SUCCESS;
  
  	return ret;
  err:
  	vrf_tx_error(dev, skb);
  	return NET_XMIT_DROP;
  }
  #else

  static netdev_tx_t vrf_process_v6_outbound(struct sk_buff *skb,
  					   struct net_device *dev)
  {

  	vrf_tx_error(dev, skb);
  	return NET_XMIT_DROP;

  }

  #endif

  /* based on ip_local_out; can't use it b/c the dst is switched pointing to us */
  static int vrf_ip_local_out(struct net *net, struct sock *sk,
  			    struct sk_buff *skb)
  {
  	int err;
  
  	err = nf_hook(NFPROTO_IPV4, NF_INET_LOCAL_OUT, net, sk,
  		      skb, NULL, skb_dst(skb)->dev, dst_output);
  	if (likely(err == 1))
  		err = dst_output(net, sk, skb);
  
  	return err;
  }

  static netdev_tx_t vrf_process_v4_outbound(struct sk_buff *skb,
  					   struct net_device *vrf_dev)
  {

  	struct iphdr *ip4h;

  	int ret = NET_XMIT_DROP;

  	struct flowi4 fl4;

  	struct net *net = dev_net(vrf_dev);
  	struct rtable *rt;

  	if (!pskb_may_pull(skb, ETH_HLEN + sizeof(struct iphdr)))
  		goto err;
  
  	ip4h = ip_hdr(skb);
  
  	memset(&fl4, 0, sizeof(fl4));
  	/* needed to match OIF rule */
  	fl4.flowi4_oif = vrf_dev->ifindex;
  	fl4.flowi4_iif = LOOPBACK_IFINDEX;
  	fl4.flowi4_tos = RT_TOS(ip4h->tos);
  	fl4.flowi4_flags = FLOWI_FLAG_ANYSRC | FLOWI_FLAG_SKIP_NH_OIF;
  	fl4.flowi4_proto = ip4h->protocol;
  	fl4.daddr = ip4h->daddr;
  	fl4.saddr = ip4h->saddr;

  	rt = ip_route_output_flow(net, &fl4, NULL);
  	if (IS_ERR(rt))
  		goto err;

  	skb_dst_drop(skb);

  
  	/* if dst.dev is loopback or the VRF device again this is locally
  	 * originated traffic destined to a local address. Short circuit

  	 * to Rx path

  	 */

  	if (rt->dst.dev == vrf_dev)
  		return vrf_local_xmit(skb, vrf_dev, &rt->dst);

  	skb_dst_set(skb, &rt->dst);
  
  	/* strip the ethernet header added for pass through VRF device */
  	__skb_pull(skb, skb_network_offset(skb));

  
  	if (!ip4h->saddr) {
  		ip4h->saddr = inet_select_addr(skb_dst(skb)->dev, 0,
  					       RT_SCOPE_LINK);
  	}

  	ret = vrf_ip_local_out(dev_net(skb_dst(skb)->dev), skb->sk, skb);

  	if (unlikely(net_xmit_eval(ret)))
  		vrf_dev->stats.tx_errors++;
  	else
  		ret = NET_XMIT_SUCCESS;
  
  out:
  	return ret;
  err:

  	vrf_tx_error(vrf_dev, skb);

  	goto out;
  }
  
  static netdev_tx_t is_ip_tx_frame(struct sk_buff *skb, struct net_device *dev)
  {
  	switch (skb->protocol) {
  	case htons(ETH_P_IP):
  		return vrf_process_v4_outbound(skb, dev);
  	case htons(ETH_P_IPV6):
  		return vrf_process_v6_outbound(skb, dev);
  	default:

  		vrf_tx_error(dev, skb);

  		return NET_XMIT_DROP;
  	}
  }
  
  static netdev_tx_t vrf_xmit(struct sk_buff *skb, struct net_device *dev)
  {

  	int len = skb->len;

  	netdev_tx_t ret = is_ip_tx_frame(skb, dev);
  
  	if (likely(ret == NET_XMIT_SUCCESS || ret == NET_XMIT_CN)) {
  		struct pcpu_dstats *dstats = this_cpu_ptr(dev->dstats);
  
  		u64_stats_update_begin(&dstats->syncp);
  		dstats->tx_pkts++;

  		dstats->tx_bytes += len;

  		u64_stats_update_end(&dstats->syncp);
  	} else {
  		this_cpu_inc(dev->dstats->tx_drps);
  	}
  
  	return ret;
  }

  static int vrf_finish_direct(struct net *net, struct sock *sk,
  			     struct sk_buff *skb)
  {
  	struct net_device *vrf_dev = skb->dev;
  
  	if (!list_empty(&vrf_dev->ptype_all) &&
  	    likely(skb_headroom(skb) >= ETH_HLEN)) {

  		struct ethhdr *eth = skb_push(skb, ETH_HLEN);

  
  		ether_addr_copy(eth->h_source, vrf_dev->dev_addr);
  		eth_zero_addr(eth->h_dest);
  		eth->h_proto = skb->protocol;
  
  		rcu_read_lock_bh();
  		dev_queue_xmit_nit(skb, vrf_dev);
  		rcu_read_unlock_bh();
  
  		skb_pull(skb, ETH_HLEN);
  	}
  
  	return 1;
  }

  #if IS_ENABLED(CONFIG_IPV6)

  /* modelled after ip6_finish_output2 */
  static int vrf_finish_output6(struct net *net, struct sock *sk,
  			      struct sk_buff *skb)
  {
  	struct dst_entry *dst = skb_dst(skb);
  	struct net_device *dev = dst->dev;

  	const struct in6_addr *nexthop;

  	struct neighbour *neigh;

  	int ret;

  	nf_reset_ct(skb);

  	skb->protocol = htons(ETH_P_IPV6);
  	skb->dev = dev;
  
  	rcu_read_lock_bh();
  	nexthop = rt6_nexthop((struct rt6_info *)dst, &ipv6_hdr(skb)->daddr);
  	neigh = __ipv6_neigh_lookup_noref(dst->dev, nexthop);
  	if (unlikely(!neigh))
  		neigh = __neigh_create(&nd_tbl, nexthop, dst->dev, false);
  	if (!IS_ERR(neigh)) {

  		sock_confirm_neigh(skb, neigh);

  		ret = neigh_output(neigh, skb, false);

  		rcu_read_unlock_bh();
  		return ret;
  	}
  	rcu_read_unlock_bh();
  
  	IP6_INC_STATS(dev_net(dst->dev),
  		      ip6_dst_idev(dst), IPSTATS_MIB_OUTNOROUTES);
  	kfree_skb(skb);
  	return -EINVAL;
  }
  
  /* modelled after ip6_output */
  static int vrf_output6(struct net *net, struct sock *sk, struct sk_buff *skb)
  {
  	return NF_HOOK_COND(NFPROTO_IPV6, NF_INET_POST_ROUTING,
  			    net, sk, skb, NULL, skb_dst(skb)->dev,
  			    vrf_finish_output6,
  			    !(IP6CB(skb)->flags & IP6SKB_REROUTED));
  }

  /* set dst on skb to send packet to us via dev_xmit path. Allows
   * packet to go through device based features such as qdisc, netfilter
   * hooks and packet sockets with skb->dev set to vrf device.
   */

  static struct sk_buff *vrf_ip6_out_redirect(struct net_device *vrf_dev,
  					    struct sk_buff *skb)

  {
  	struct net_vrf *vrf = netdev_priv(vrf_dev);
  	struct dst_entry *dst = NULL;
  	struct rt6_info *rt6;

  	rcu_read_lock();
  
  	rt6 = rcu_dereference(vrf->rt6);
  	if (likely(rt6)) {
  		dst = &rt6->dst;
  		dst_hold(dst);
  	}
  
  	rcu_read_unlock();
  
  	if (unlikely(!dst)) {
  		vrf_tx_error(vrf_dev, skb);
  		return NULL;
  	}
  
  	skb_dst_drop(skb);
  	skb_dst_set(skb, dst);
  
  	return skb;
  }

  static int vrf_output6_direct(struct net *net, struct sock *sk,
  			      struct sk_buff *skb)
  {
  	skb->protocol = htons(ETH_P_IPV6);
  
  	return NF_HOOK_COND(NFPROTO_IPV6, NF_INET_POST_ROUTING,
  			    net, sk, skb, NULL, skb->dev,
  			    vrf_finish_direct,
  			    !(IPCB(skb)->flags & IPSKB_REROUTED));
  }
  
  static struct sk_buff *vrf_ip6_out_direct(struct net_device *vrf_dev,
  					  struct sock *sk,
  					  struct sk_buff *skb)
  {
  	struct net *net = dev_net(vrf_dev);
  	int err;
  
  	skb->dev = vrf_dev;
  
  	err = nf_hook(NFPROTO_IPV6, NF_INET_LOCAL_OUT, net, sk,
  		      skb, NULL, vrf_dev, vrf_output6_direct);
  
  	if (likely(err == 1))
  		err = vrf_output6_direct(net, sk, skb);
  
  	/* reset skb device */
  	if (likely(err == 1))

  		nf_reset_ct(skb);

  	else
  		skb = NULL;
  
  	return skb;
  }
  
  static struct sk_buff *vrf_ip6_out(struct net_device *vrf_dev,
  				   struct sock *sk,
  				   struct sk_buff *skb)
  {
  	/* don't divert link scope packets */
  	if (rt6_need_strict(&ipv6_hdr(skb)->daddr))
  		return skb;
  
  	if (qdisc_tx_is_default(vrf_dev))
  		return vrf_ip6_out_direct(vrf_dev, sk, skb);
  
  	return vrf_ip6_out_redirect(vrf_dev, skb);
  }

  /* holding rtnl */

  static void vrf_rt6_release(struct net_device *dev, struct net_vrf *vrf)

  {

  	struct rt6_info *rt6 = rtnl_dereference(vrf->rt6);

  	struct net *net = dev_net(dev);
  	struct dst_entry *dst;

  	RCU_INIT_POINTER(vrf->rt6, NULL);

  	synchronize_rcu();

  	/* move dev in dst's to loopback so this VRF device can be deleted
  	 * - based on dst_ifdown
  	 */
  	if (rt6) {
  		dst = &rt6->dst;
  		dev_put(dst->dev);
  		dst->dev = net->loopback_dev;
  		dev_hold(dst->dev);
  		dst_release(dst);
  	}

  }
  
  static int vrf_rt6_create(struct net_device *dev)
  {

  	int flags = DST_HOST | DST_NOPOLICY | DST_NOXFRM;

  	struct net_vrf *vrf = netdev_priv(dev);

  	struct net *net = dev_net(dev);

  	struct rt6_info *rt6;

  	int rc = -ENOMEM;

  	/* IPv6 can be CONFIG enabled and then disabled runtime */
  	if (!ipv6_mod_enabled())
  		return 0;

  	vrf->fib6_table = fib6_new_table(net, vrf->tb_id);
  	if (!vrf->fib6_table)

  		goto out;

  	/* create a dst for routing packets out a VRF device */
  	rt6 = ip6_dst_alloc(net, dev, flags);

  	if (!rt6)
  		goto out;

  	rt6->dst.output	= vrf_output6;

  	rcu_assign_pointer(vrf->rt6, rt6);

  	rc = 0;
  out:
  	return rc;
  }
  #else

  static struct sk_buff *vrf_ip6_out(struct net_device *vrf_dev,
  				   struct sock *sk,
  				   struct sk_buff *skb)
  {
  	return skb;
  }

  static void vrf_rt6_release(struct net_device *dev, struct net_vrf *vrf)

  {
  }
  
  static int vrf_rt6_create(struct net_device *dev)
  {
  	return 0;
  }
  #endif

  /* modelled after ip_finish_output2 */

  static int vrf_finish_output(struct net *net, struct sock *sk, struct sk_buff *skb)

  {

  	struct dst_entry *dst = skb_dst(skb);
  	struct rtable *rt = (struct rtable *)dst;
  	struct net_device *dev = dst->dev;
  	unsigned int hh_len = LL_RESERVED_SPACE(dev);
  	struct neighbour *neigh;

  	bool is_v6gw = false;

  	int ret = -EINVAL;

  	nf_reset_ct(skb);

  	/* Be paranoid, rather than too clever. */
  	if (unlikely(skb_headroom(skb) < hh_len && dev->header_ops)) {
  		struct sk_buff *skb2;
  
  		skb2 = skb_realloc_headroom(skb, LL_RESERVED_SPACE(dev));
  		if (!skb2) {
  			ret = -ENOMEM;
  			goto err;
  		}
  		if (skb->sk)
  			skb_set_owner_w(skb2, skb->sk);
  
  		consume_skb(skb);
  		skb = skb2;
  	}
  
  	rcu_read_lock_bh();

  	neigh = ip_neigh_for_gw(rt, skb, &is_v6gw);

  	if (!IS_ERR(neigh)) {
  		sock_confirm_neigh(skb, neigh);

  		/* if crossing protocols, can not use the cached header */
  		ret = neigh_output(neigh, skb, is_v6gw);

  		rcu_read_unlock_bh();
  		return ret;

  	}

  
  	rcu_read_unlock_bh();
  err:

  	vrf_tx_error(skb->dev, skb);

  	return ret;

  }

  static int vrf_output(struct net *net, struct sock *sk, struct sk_buff *skb)

  {
  	struct net_device *dev = skb_dst(skb)->dev;

  	IP_UPD_PO_STATS(net, IPSTATS_MIB_OUT, skb->len);

  
  	skb->dev = dev;
  	skb->protocol = htons(ETH_P_IP);

  	return NF_HOOK_COND(NFPROTO_IPV4, NF_INET_POST_ROUTING,
  			    net, sk, skb, NULL, dev,

  			    vrf_finish_output,

  			    !(IPCB(skb)->flags & IPSKB_REROUTED));
  }

  /* set dst on skb to send packet to us via dev_xmit path. Allows
   * packet to go through device based features such as qdisc, netfilter
   * hooks and packet sockets with skb->dev set to vrf device.
   */

  static struct sk_buff *vrf_ip_out_redirect(struct net_device *vrf_dev,
  					   struct sk_buff *skb)

  {
  	struct net_vrf *vrf = netdev_priv(vrf_dev);
  	struct dst_entry *dst = NULL;
  	struct rtable *rth;
  
  	rcu_read_lock();
  
  	rth = rcu_dereference(vrf->rth);
  	if (likely(rth)) {
  		dst = &rth->dst;
  		dst_hold(dst);
  	}
  
  	rcu_read_unlock();
  
  	if (unlikely(!dst)) {
  		vrf_tx_error(vrf_dev, skb);
  		return NULL;
  	}
  
  	skb_dst_drop(skb);
  	skb_dst_set(skb, dst);
  
  	return skb;
  }

  static int vrf_output_direct(struct net *net, struct sock *sk,
  			     struct sk_buff *skb)
  {
  	skb->protocol = htons(ETH_P_IP);
  
  	return NF_HOOK_COND(NFPROTO_IPV4, NF_INET_POST_ROUTING,
  			    net, sk, skb, NULL, skb->dev,
  			    vrf_finish_direct,
  			    !(IPCB(skb)->flags & IPSKB_REROUTED));
  }
  
  static struct sk_buff *vrf_ip_out_direct(struct net_device *vrf_dev,
  					 struct sock *sk,
  					 struct sk_buff *skb)
  {
  	struct net *net = dev_net(vrf_dev);
  	int err;
  
  	skb->dev = vrf_dev;
  
  	err = nf_hook(NFPROTO_IPV4, NF_INET_LOCAL_OUT, net, sk,
  		      skb, NULL, vrf_dev, vrf_output_direct);
  
  	if (likely(err == 1))
  		err = vrf_output_direct(net, sk, skb);
  
  	/* reset skb device */
  	if (likely(err == 1))

  		nf_reset_ct(skb);

  	else
  		skb = NULL;
  
  	return skb;
  }
  
  static struct sk_buff *vrf_ip_out(struct net_device *vrf_dev,
  				  struct sock *sk,
  				  struct sk_buff *skb)
  {

  	/* don't divert multicast or local broadcast */
  	if (ipv4_is_multicast(ip_hdr(skb)->daddr) ||
  	    ipv4_is_lbcast(ip_hdr(skb)->daddr))

  		return skb;
  
  	if (qdisc_tx_is_default(vrf_dev))
  		return vrf_ip_out_direct(vrf_dev, sk, skb);
  
  	return vrf_ip_out_redirect(vrf_dev, skb);
  }

  /* called with rcu lock held */
  static struct sk_buff *vrf_l3_out(struct net_device *vrf_dev,
  				  struct sock *sk,
  				  struct sk_buff *skb,
  				  u16 proto)
  {
  	switch (proto) {
  	case AF_INET:
  		return vrf_ip_out(vrf_dev, sk, skb);

  	case AF_INET6:
  		return vrf_ip6_out(vrf_dev, sk, skb);

  	}
  
  	return skb;
  }

  /* holding rtnl */

  static void vrf_rtable_release(struct net_device *dev, struct net_vrf *vrf)

  {

  	struct rtable *rth = rtnl_dereference(vrf->rth);

  	struct net *net = dev_net(dev);
  	struct dst_entry *dst;

  	RCU_INIT_POINTER(vrf->rth, NULL);

  	synchronize_rcu();

  	/* move dev in dst's to loopback so this VRF device can be deleted
  	 * - based on dst_ifdown
  	 */
  	if (rth) {
  		dst = &rth->dst;
  		dev_put(dst->dev);
  		dst->dev = net->loopback_dev;
  		dev_hold(dst->dev);
  		dst_release(dst);
  	}

  }

  static int vrf_rtable_create(struct net_device *dev)

  {

  	struct net_vrf *vrf = netdev_priv(dev);

  	struct rtable *rth;

  	if (!fib_new_table(dev_net(dev), vrf->tb_id))

  		return -ENOMEM;

  	/* create a dst for routing packets out through a VRF device */

  	rth = rt_dst_alloc(dev, 0, RTN_UNICAST, 1, 1, 0);

  	if (!rth)
  		return -ENOMEM;

  	rth->dst.output	= vrf_output;

  
  	rcu_assign_pointer(vrf->rth, rth);
  
  	return 0;

  }
  
  /**************************** device handling ********************/
  
  /* cycle interface to flush neighbor cache and move routes across tables */

  static void cycle_netdev(struct net_device *dev,
  			 struct netlink_ext_ack *extack)

  {
  	unsigned int flags = dev->flags;
  	int ret;
  
  	if (!netif_running(dev))
  		return;

  	ret = dev_change_flags(dev, flags & ~IFF_UP, extack);

  	if (ret >= 0)

  		ret = dev_change_flags(dev, flags, extack);

  
  	if (ret < 0) {
  		netdev_err(dev,
  			   "Failed to cycle device %s; route tables might be wrong!
  ",
  			   dev->name);
  	}
  }

  static int do_vrf_add_slave(struct net_device *dev, struct net_device *port_dev,
  			    struct netlink_ext_ack *extack)

  {

  	int ret;

  	/* do not allow loopback device to be enslaved to a VRF.
  	 * The vrf device acts as the loopback for the vrf.
  	 */

  	if (port_dev == dev_net(dev)->loopback_dev) {
  		NL_SET_ERR_MSG(extack,
  			       "Can not enslave loopback device to a VRF");

  		return -EOPNOTSUPP;

  	}

  	port_dev->priv_flags |= IFF_L3MDEV_SLAVE;

  	ret = netdev_master_upper_dev_link(port_dev, dev, NULL, NULL, extack);

  	if (ret < 0)

  		goto err;

  	cycle_netdev(port_dev, extack);

  
  	return 0;

  
  err:
  	port_dev->priv_flags &= ~IFF_L3MDEV_SLAVE;
  	return ret;

  }

  static int vrf_add_slave(struct net_device *dev, struct net_device *port_dev,
  			 struct netlink_ext_ack *extack)

  {

  	if (netif_is_l3_master(port_dev)) {
  		NL_SET_ERR_MSG(extack,
  			       "Can not enslave an L3 master device to a VRF");
  		return -EINVAL;
  	}
  
  	if (netif_is_l3_slave(port_dev))

  		return -EINVAL;

  	return do_vrf_add_slave(dev, port_dev, extack);

  }
  
  /* inverse of do_vrf_add_slave */
  static int do_vrf_del_slave(struct net_device *dev, struct net_device *port_dev)
  {

  	netdev_upper_dev_unlink(port_dev, dev);

  	port_dev->priv_flags &= ~IFF_L3MDEV_SLAVE;

  	cycle_netdev(port_dev, NULL);

  	return 0;
  }
  
  static int vrf_del_slave(struct net_device *dev, struct net_device *port_dev)
  {

  	return do_vrf_del_slave(dev, port_dev);
  }
  
  static void vrf_dev_uninit(struct net_device *dev)
  {
  	struct net_vrf *vrf = netdev_priv(dev);

  	vrf_rtable_release(dev, vrf);
  	vrf_rt6_release(dev, vrf);

  	free_percpu(dev->dstats);

  	dev->dstats = NULL;
  }
  
  static int vrf_dev_init(struct net_device *dev)
  {
  	struct net_vrf *vrf = netdev_priv(dev);

  	dev->dstats = netdev_alloc_pcpu_stats(struct pcpu_dstats);
  	if (!dev->dstats)
  		goto out_nomem;
  
  	/* create the default dst which points back to us */

  	if (vrf_rtable_create(dev) != 0)

  		goto out_stats;

  	if (vrf_rt6_create(dev) != 0)
  		goto out_rth;

  	dev->flags = IFF_MASTER | IFF_NOARP;

  	/* MTU is irrelevant for VRF device; set to 64k similar to lo */
  	dev->mtu = 64 * 1024;
  
  	/* similarly, oper state is irrelevant; set to up to avoid confusion */
  	dev->operstate = IF_OPER_UP;

  	return 0;

  out_rth:

  	vrf_rtable_release(dev, vrf);

  out_stats:
  	free_percpu(dev->dstats);
  	dev->dstats = NULL;
  out_nomem:
  	return -ENOMEM;
  }
  
  static const struct net_device_ops vrf_netdev_ops = {
  	.ndo_init		= vrf_dev_init,
  	.ndo_uninit		= vrf_dev_uninit,
  	.ndo_start_xmit		= vrf_xmit,

  	.ndo_set_mac_address	= eth_mac_addr,

  	.ndo_get_stats64	= vrf_get_stats64,
  	.ndo_add_slave		= vrf_add_slave,
  	.ndo_del_slave		= vrf_del_slave,
  };

  static u32 vrf_fib_table(const struct net_device *dev)
  {
  	struct net_vrf *vrf = netdev_priv(dev);
  
  	return vrf->tb_id;
  }

  static int vrf_rcv_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
  {

  	kfree_skb(skb);

  	return 0;
  }
  
  static struct sk_buff *vrf_rcv_nfhook(u8 pf, unsigned int hook,
  				      struct sk_buff *skb,
  				      struct net_device *dev)
  {
  	struct net *net = dev_net(dev);

  	if (nf_hook(pf, hook, net, NULL, skb, dev, NULL, vrf_rcv_finish) != 1)

  		skb = NULL;    /* kfree_skb(skb) handled by nf code */
  
  	return skb;
  }

  #if IS_ENABLED(CONFIG_IPV6)

  /* neighbor handling is done with actual device; do not want
   * to flip skb->dev for those ndisc packets. This really fails
   * for multiple next protocols (e.g., NEXTHDR_HOP). But it is
   * a start.
   */
  static bool ipv6_ndisc_frame(const struct sk_buff *skb)
  {
  	const struct ipv6hdr *iph = ipv6_hdr(skb);
  	bool rc = false;
  
  	if (iph->nexthdr == NEXTHDR_ICMP) {
  		const struct icmp6hdr *icmph;
  		struct icmp6hdr _icmph;
  
  		icmph = skb_header_pointer(skb, sizeof(*iph),
  					   sizeof(_icmph), &_icmph);
  		if (!icmph)
  			goto out;
  
  		switch (icmph->icmp6_type) {
  		case NDISC_ROUTER_SOLICITATION:
  		case NDISC_ROUTER_ADVERTISEMENT:
  		case NDISC_NEIGHBOUR_SOLICITATION:
  		case NDISC_NEIGHBOUR_ADVERTISEMENT:
  		case NDISC_REDIRECT:
  			rc = true;
  			break;
  		}
  	}
  
  out:
  	return rc;
  }

  static struct rt6_info *vrf_ip6_route_lookup(struct net *net,
  					     const struct net_device *dev,
  					     struct flowi6 *fl6,
  					     int ifindex,

  					     const struct sk_buff *skb,

  					     int flags)
  {
  	struct net_vrf *vrf = netdev_priv(dev);

  	return ip6_pol_route(net, vrf->fib6_table, ifindex, fl6, skb, flags);

  }
  
  static void vrf_ip6_input_dst(struct sk_buff *skb, struct net_device *vrf_dev,
  			      int ifindex)
  {
  	const struct ipv6hdr *iph = ipv6_hdr(skb);
  	struct flowi6 fl6 = {

  		.flowi6_iif     = ifindex,
  		.flowi6_mark    = skb->mark,
  		.flowi6_proto   = iph->nexthdr,

  		.daddr          = iph->daddr,
  		.saddr          = iph->saddr,
  		.flowlabel      = ip6_flowinfo(iph),

  	};
  	struct net *net = dev_net(vrf_dev);
  	struct rt6_info *rt6;

  	rt6 = vrf_ip6_route_lookup(net, vrf_dev, &fl6, ifindex, skb,

  				   RT6_LOOKUP_F_HAS_SADDR | RT6_LOOKUP_F_IFACE);
  	if (unlikely(!rt6))
  		return;
  
  	if (unlikely(&rt6->dst == &net->ipv6.ip6_null_entry->dst))
  		return;
  
  	skb_dst_set(skb, &rt6->dst);
  }

  static struct sk_buff *vrf_ip6_rcv(struct net_device *vrf_dev,
  				   struct sk_buff *skb)
  {

  	int orig_iif = skb->skb_iif;

  	bool need_strict = rt6_need_strict(&ipv6_hdr(skb)->daddr);
  	bool is_ndisc = ipv6_ndisc_frame(skb);

  	/* loopback, multicast & non-ND link-local traffic; do not push through
  	 * packet taps again. Reset pkt_type for upper layers to process skb

  	 */

  	if (skb->pkt_type == PACKET_LOOPBACK || (need_strict && !is_ndisc)) {

  		skb->dev = vrf_dev;
  		skb->skb_iif = vrf_dev->ifindex;

  		IP6CB(skb)->flags |= IP6SKB_L3SLAVE;

  		if (skb->pkt_type == PACKET_LOOPBACK)
  			skb->pkt_type = PACKET_HOST;

  		goto out;
  	}

  	/* if packet is NDISC then keep the ingress interface */
  	if (!is_ndisc) {

  		vrf_rx_stats(vrf_dev, skb->len);

  		skb->dev = vrf_dev;
  		skb->skb_iif = vrf_dev->ifindex;

  		if (!list_empty(&vrf_dev->ptype_all)) {
  			skb_push(skb, skb->mac_len);
  			dev_queue_xmit_nit(skb, vrf_dev);
  			skb_pull(skb, skb->mac_len);
  		}

  
  		IP6CB(skb)->flags |= IP6SKB_L3SLAVE;
  	}

  	if (need_strict)
  		vrf_ip6_input_dst(skb, vrf_dev, orig_iif);

  	skb = vrf_rcv_nfhook(NFPROTO_IPV6, NF_INET_PRE_ROUTING, skb, vrf_dev);

  out:

  	return skb;
  }
  
  #else
  static struct sk_buff *vrf_ip6_rcv(struct net_device *vrf_dev,
  				   struct sk_buff *skb)
  {
  	return skb;
  }
  #endif
  
  static struct sk_buff *vrf_ip_rcv(struct net_device *vrf_dev,
  				  struct sk_buff *skb)
  {
  	skb->dev = vrf_dev;
  	skb->skb_iif = vrf_dev->ifindex;

  	IPCB(skb)->flags |= IPSKB_L3SLAVE;

  	if (ipv4_is_multicast(ip_hdr(skb)->daddr))
  		goto out;

  	/* loopback traffic; do not push through packet taps again.
  	 * Reset pkt_type for upper layers to process skb
  	 */
  	if (skb->pkt_type == PACKET_LOOPBACK) {
  		skb->pkt_type = PACKET_HOST;
  		goto out;
  	}

  	vrf_rx_stats(vrf_dev, skb->len);

  	if (!list_empty(&vrf_dev->ptype_all)) {
  		skb_push(skb, skb->mac_len);
  		dev_queue_xmit_nit(skb, vrf_dev);
  		skb_pull(skb, skb->mac_len);
  	}

  	skb = vrf_rcv_nfhook(NFPROTO_IPV4, NF_INET_PRE_ROUTING, skb, vrf_dev);

  out:

  	return skb;
  }
  
  /* called with rcu lock held */
  static struct sk_buff *vrf_l3_rcv(struct net_device *vrf_dev,
  				  struct sk_buff *skb,
  				  u16 proto)
  {
  	switch (proto) {
  	case AF_INET:
  		return vrf_ip_rcv(vrf_dev, skb);
  	case AF_INET6:
  		return vrf_ip6_rcv(vrf_dev, skb);
  	}
  
  	return skb;
  }
  
  #if IS_ENABLED(CONFIG_IPV6)

  /* send to link-local or multicast address via interface enslaved to
   * VRF device. Force lookup to VRF table without changing flow struct

   * Note: Caller to this function must hold rcu_read_lock() and no refcnt
   * is taken on the dst by this function.

   */
  static struct dst_entry *vrf_link_scope_lookup(const struct net_device *dev,
  					      struct flowi6 *fl6)

  {

  	struct net *net = dev_net(dev);

  	int flags = RT6_LOOKUP_F_IFACE | RT6_LOOKUP_F_DST_NOREF;

  	struct dst_entry *dst = NULL;

  	struct rt6_info *rt;

  	/* VRF device does not have a link-local address and
  	 * sending packets to link-local or mcast addresses over
  	 * a VRF device does not make sense
  	 */
  	if (fl6->flowi6_oif == dev->ifindex) {
  		dst = &net->ipv6.ip6_null_entry->dst;

  		return dst;

  	}

  	if (!ipv6_addr_any(&fl6->saddr))
  		flags |= RT6_LOOKUP_F_HAS_SADDR;

  	rt = vrf_ip6_route_lookup(net, dev, fl6, fl6->flowi6_oif, NULL, flags);

  	if (rt)
  		dst = &rt->dst;

  	return dst;

  }
  #endif

  static const struct l3mdev_ops vrf_l3mdev_ops = {
  	.l3mdev_fib_table	= vrf_fib_table,

  	.l3mdev_l3_rcv		= vrf_l3_rcv,

  	.l3mdev_l3_out		= vrf_l3_out,

  #if IS_ENABLED(CONFIG_IPV6)

  	.l3mdev_link_scope_lookup = vrf_link_scope_lookup,

  #endif

  };

  static void vrf_get_drvinfo(struct net_device *dev,
  			    struct ethtool_drvinfo *info)
  {
  	strlcpy(info->driver, DRV_NAME, sizeof(info->driver));
  	strlcpy(info->version, DRV_VERSION, sizeof(info->version));
  }
  
  static const struct ethtool_ops vrf_ethtool_ops = {
  	.get_drvinfo	= vrf_get_drvinfo,
  };

  static inline size_t vrf_fib_rule_nl_size(void)
  {
  	size_t sz;
  
  	sz  = NLMSG_ALIGN(sizeof(struct fib_rule_hdr));
  	sz += nla_total_size(sizeof(u8));	/* FRA_L3MDEV */
  	sz += nla_total_size(sizeof(u32));	/* FRA_PRIORITY */

  	sz += nla_total_size(sizeof(u8));       /* FRA_PROTOCOL */

  
  	return sz;
  }
  
  static int vrf_fib_rule(const struct net_device *dev, __u8 family, bool add_it)
  {
  	struct fib_rule_hdr *frh;
  	struct nlmsghdr *nlh;
  	struct sk_buff *skb;
  	int err;

  	if ((family == AF_INET6 || family == RTNL_FAMILY_IP6MR) &&
  	    !ipv6_mod_enabled())

  		return 0;

  	skb = nlmsg_new(vrf_fib_rule_nl_size(), GFP_KERNEL);
  	if (!skb)
  		return -ENOMEM;
  
  	nlh = nlmsg_put(skb, 0, 0, 0, sizeof(*frh), 0);
  	if (!nlh)
  		goto nla_put_failure;
  
  	/* rule only needs to appear once */

  	nlh->nlmsg_flags |= NLM_F_EXCL;

  
  	frh = nlmsg_data(nlh);
  	memset(frh, 0, sizeof(*frh));
  	frh->family = family;
  	frh->action = FR_ACT_TO_TBL;

  
  	if (nla_put_u8(skb, FRA_PROTOCOL, RTPROT_KERNEL))
  		goto nla_put_failure;

  	if (nla_put_u8(skb, FRA_L3MDEV, 1))

  		goto nla_put_failure;
  
  	if (nla_put_u32(skb, FRA_PRIORITY, FIB_RULE_PREF))
  		goto nla_put_failure;
  
  	nlmsg_end(skb, nlh);
  
  	/* fib_nl_{new,del}rule handling looks for net from skb->sk */
  	skb->sk = dev_net(dev)->rtnl;
  	if (add_it) {

  		err = fib_nl_newrule(skb, nlh, NULL);

  		if (err == -EEXIST)
  			err = 0;
  	} else {

  		err = fib_nl_delrule(skb, nlh, NULL);

  		if (err == -ENOENT)
  			err = 0;
  	}
  	nlmsg_free(skb);
  
  	return err;
  
  nla_put_failure:
  	nlmsg_free(skb);
  
  	return -EMSGSIZE;
  }
  
  static int vrf_add_fib_rules(const struct net_device *dev)
  {
  	int err;
  
  	err = vrf_fib_rule(dev, AF_INET,  true);
  	if (err < 0)
  		goto out_err;
  
  	err = vrf_fib_rule(dev, AF_INET6, true);
  	if (err < 0)
  		goto ipv6_err;

  #if IS_ENABLED(CONFIG_IP_MROUTE_MULTIPLE_TABLES)
  	err = vrf_fib_rule(dev, RTNL_FAMILY_IPMR, true);
  	if (err < 0)
  		goto ipmr_err;
  #endif

  #if IS_ENABLED(CONFIG_IPV6_MROUTE_MULTIPLE_TABLES)
  	err = vrf_fib_rule(dev, RTNL_FAMILY_IP6MR, true);
  	if (err < 0)
  		goto ip6mr_err;
  #endif

  	return 0;

  #if IS_ENABLED(CONFIG_IPV6_MROUTE_MULTIPLE_TABLES)
  ip6mr_err:
  	vrf_fib_rule(dev, RTNL_FAMILY_IPMR,  false);
  #endif

  #if IS_ENABLED(CONFIG_IP_MROUTE_MULTIPLE_TABLES)
  ipmr_err:
  	vrf_fib_rule(dev, AF_INET6,  false);
  #endif

  ipv6_err:
  	vrf_fib_rule(dev, AF_INET,  false);
  
  out_err:
  	netdev_err(dev, "Failed to add FIB rules.
  ");
  	return err;
  }

  static void vrf_setup(struct net_device *dev)
  {
  	ether_setup(dev);
  
  	/* Initialize the device structure. */
  	dev->netdev_ops = &vrf_netdev_ops;

  	dev->l3mdev_ops = &vrf_l3mdev_ops;

  	dev->ethtool_ops = &vrf_ethtool_ops;

  	dev->needs_free_netdev = true;

  
  	/* Fill in device structure with ethernet-generic values. */
  	eth_hw_addr_random(dev);
  
  	/* don't acquire vrf device's netif_tx_lock when transmitting */
  	dev->features |= NETIF_F_LLTX;
  
  	/* don't allow vrf devices to change network namespaces. */
  	dev->features |= NETIF_F_NETNS_LOCAL;

  
  	/* does not make sense for a VLAN to be added to a vrf device */
  	dev->features   |= NETIF_F_VLAN_CHALLENGED;
  
  	/* enable offload features */
  	dev->features   |= NETIF_F_GSO_SOFTWARE;

  	dev->features   |= NETIF_F_RXCSUM | NETIF_F_HW_CSUM | NETIF_F_SCTP_CRC;

  	dev->features   |= NETIF_F_SG | NETIF_F_FRAGLIST | NETIF_F_HIGHDMA;
  
  	dev->hw_features = dev->features;
  	dev->hw_enc_features = dev->features;
  
  	/* default to no qdisc; user can add if desired */
  	dev->priv_flags |= IFF_NO_QUEUE;

  	dev->priv_flags |= IFF_NO_RX_HANDLER;

  	dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;

  	/* VRF devices do not care about MTU, but if the MTU is set
  	 * too low then the ipv4 and ipv6 protocols are disabled
  	 * which breaks networking.
  	 */
  	dev->min_mtu = IPV6_MIN_MTU;
  	dev->max_mtu = ETH_MAX_MTU;

  }

  static int vrf_validate(struct nlattr *tb[], struct nlattr *data[],
  			struct netlink_ext_ack *extack)

  {
  	if (tb[IFLA_ADDRESS]) {

  		if (nla_len(tb[IFLA_ADDRESS]) != ETH_ALEN) {
  			NL_SET_ERR_MSG(extack, "Invalid hardware address");

  			return -EINVAL;

  		}
  		if (!is_valid_ether_addr(nla_data(tb[IFLA_ADDRESS]))) {
  			NL_SET_ERR_MSG(extack, "Invalid hardware address");

  			return -EADDRNOTAVAIL;

  		}

  	}
  	return 0;
  }
  
  static void vrf_dellink(struct net_device *dev, struct list_head *head)
  {

  	struct net_device *port_dev;
  	struct list_head *iter;
  
  	netdev_for_each_lower_dev(dev, port_dev, iter)
  		vrf_del_slave(dev, port_dev);

  	unregister_netdevice_queue(dev, head);
  }
  
  static int vrf_newlink(struct net *src_net, struct net_device *dev,

  		       struct nlattr *tb[], struct nlattr *data[],
  		       struct netlink_ext_ack *extack)

  {
  	struct net_vrf *vrf = netdev_priv(dev);

  	bool *add_fib_rules;
  	struct net *net;

  	int err;

  	if (!data || !data[IFLA_VRF_TABLE]) {
  		NL_SET_ERR_MSG(extack, "VRF table id is missing");

  		return -EINVAL;

  	}

  
  	vrf->tb_id = nla_get_u32(data[IFLA_VRF_TABLE]);

  	if (vrf->tb_id == RT_TABLE_UNSPEC) {
  		NL_SET_ERR_MSG_ATTR(extack, data[IFLA_VRF_TABLE],
  				    "Invalid VRF table id");

  		return -EINVAL;

  	}

  	dev->priv_flags |= IFF_L3MDEV_MASTER;

  	err = register_netdevice(dev);
  	if (err)
  		goto out;

  	net = dev_net(dev);
  	add_fib_rules = net_generic(net, vrf_net_id);
  	if (*add_fib_rules) {

  		err = vrf_add_fib_rules(dev);
  		if (err) {
  			unregister_netdevice(dev);
  			goto out;
  		}

  		*add_fib_rules = false;

  	}
  
  out:
  	return err;

  }
  
  static size_t vrf_nl_getsize(const struct net_device *dev)
  {
  	return nla_total_size(sizeof(u32));  /* IFLA_VRF_TABLE */
  }
  
  static int vrf_fillinfo(struct sk_buff *skb,
  			const struct net_device *dev)
  {
  	struct net_vrf *vrf = netdev_priv(dev);
  
  	return nla_put_u32(skb, IFLA_VRF_TABLE, vrf->tb_id);
  }

  static size_t vrf_get_slave_size(const struct net_device *bond_dev,
  				 const struct net_device *slave_dev)
  {
  	return nla_total_size(sizeof(u32));  /* IFLA_VRF_PORT_TABLE */
  }
  
  static int vrf_fill_slave_info(struct sk_buff *skb,
  			       const struct net_device *vrf_dev,
  			       const struct net_device *slave_dev)
  {
  	struct net_vrf *vrf = netdev_priv(vrf_dev);
  
  	if (nla_put_u32(skb, IFLA_VRF_PORT_TABLE, vrf->tb_id))
  		return -EMSGSIZE;
  
  	return 0;
  }

  static const struct nla_policy vrf_nl_policy[IFLA_VRF_MAX + 1] = {
  	[IFLA_VRF_TABLE] = { .type = NLA_U32 },
  };
  
  static struct rtnl_link_ops vrf_link_ops __read_mostly = {
  	.kind		= DRV_NAME,
  	.priv_size	= sizeof(struct net_vrf),
  
  	.get_size	= vrf_nl_getsize,
  	.policy		= vrf_nl_policy,
  	.validate	= vrf_validate,
  	.fill_info	= vrf_fillinfo,

  	.get_slave_size  = vrf_get_slave_size,
  	.fill_slave_info = vrf_fill_slave_info,

  	.newlink	= vrf_newlink,
  	.dellink	= vrf_dellink,
  	.setup		= vrf_setup,
  	.maxtype	= IFLA_VRF_MAX,
  };
  
  static int vrf_device_event(struct notifier_block *unused,
  			    unsigned long event, void *ptr)
  {
  	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
  
  	/* only care about unregister events to drop slave references */
  	if (event == NETDEV_UNREGISTER) {

  		struct net_device *vrf_dev;

  		if (!netif_is_l3_slave(dev))

  			goto out;

  		vrf_dev = netdev_master_upper_dev_get(dev);
  		vrf_del_slave(vrf_dev, dev);

  	}
  out:
  	return NOTIFY_DONE;
  }
  
  static struct notifier_block vrf_notifier_block __read_mostly = {
  	.notifier_call = vrf_device_event,
  };

  /* Initialize per network namespace state */
  static int __net_init vrf_netns_init(struct net *net)
  {
  	bool *add_fib_rules = net_generic(net, vrf_net_id);
  
  	*add_fib_rules = true;
  
  	return 0;
  }
  
  static struct pernet_operations vrf_net_ops __net_initdata = {
  	.init = vrf_netns_init,
  	.id   = &vrf_net_id,
  	.size = sizeof(bool),
  };

  static int __init vrf_init_module(void)
  {
  	int rc;

  	register_netdevice_notifier(&vrf_notifier_block);

  	rc = register_pernet_subsys(&vrf_net_ops);

  	if (rc < 0)
  		goto error;

  	rc = rtnl_link_register(&vrf_link_ops);
  	if (rc < 0) {
  		unregister_pernet_subsys(&vrf_net_ops);
  		goto error;
  	}

  	return 0;
  
  error:
  	unregister_netdevice_notifier(&vrf_notifier_block);

  	return rc;
  }

  module_init(vrf_init_module);

  MODULE_AUTHOR("Shrijeet Mukherjee, David Ahern");
  MODULE_DESCRIPTION("Device driver to instantiate VRF domains");
  MODULE_LICENSE("GPL");
  MODULE_ALIAS_RTNL_LINK(DRV_NAME);
  MODULE_VERSION(DRV_VERSION);