static
struct net_device *ipmr_new_tunnel(struct vifctl *v)
{
	struct net_device  *dev;

	dev = __dev_get_by_name(&init_net, "tunl0");

	if (dev) {
		const struct net_device_ops *ops = dev->netdev_ops;
		int err;
		struct ifreq ifr;
		struct ip_tunnel_parm p;
		struct in_device  *in_dev;

		memset(&p, 0, sizeof(p));
		p.iph.daddr = v->vifc_rmt_addr.s_addr;
		p.iph.saddr = v->vifc_lcl_addr.s_addr;
		p.iph.version = 4;
		p.iph.ihl = 5;
		p.iph.protocol = IPPROTO_IPIP;
		sprintf(p.name, "dvmrp%d", v->vifc_vifi);
		ifr.ifr_ifru.ifru_data = (__force void __user *)&p;

		if (ops->ndo_do_ioctl) {
			mm_segment_t oldfs = get_fs();

			set_fs(KERNEL_DS);
			err = ops->ndo_do_ioctl(dev, &ifr, SIOCADDTUNNEL);
			set_fs(oldfs);
		} else
			err = -EOPNOTSUPP;

		dev = NULL;

		if (err == 0 && (dev = __dev_get_by_name(&init_net, p.name)) != NULL) {
			dev->flags |= IFF_MULTICAST;

			in_dev = __in_dev_get_rtnl(dev);
			if (in_dev == NULL)
				goto failure;

			ipv4_devconf_setall(in_dev);
			IPV4_DEVCONF(in_dev->cnf, RP_FILTER) = 0;

			if (dev_open(dev))
				goto failure;
			dev_hold(dev);
		}
	}
	return dev;

failure:
	/* allow the register to be completed before unregistering. */
	rtnl_unlock();
	rtnl_lock();

	unregister_netdevice(dev);
	return NULL;
}

static struct ip_tunnel * ipip_tunnel_locate(struct ip_tunnel_parm *parms, int create)
{
    u32 remote = parms->iph.daddr;
    u32 local = parms->iph.saddr;
    struct ip_tunnel *t, **tp, *nt;
    struct net_device *dev;
    unsigned h = 0;
    int prio = 0;
    char name[IFNAMSIZ];

    if (remote) {
        prio |= 2;
        h ^= HASH(remote);
    }
    if (local) {
        prio |= 1;
        h ^= HASH(local);
    }
    for (tp = &tunnels[prio][h]; (t = *tp) != NULL; tp = &t->next) {
        if (local == t->parms.iph.saddr && remote == t->parms.iph.daddr)
            return t;
    }
    if (!create)
        return NULL;

    if (parms->name[0])
        strlcpy(name, parms->name, IFNAMSIZ);
    else {
        int i;
        for (i=1; i<100; i++) {
            sprintf(name, "tunl%d", i);
            if (__dev_get_by_name(name) == NULL)
                break;
        }
        if (i==100)
            goto failed;
    }

    dev = alloc_netdev(sizeof(*t), name, ipip_tunnel_setup);
    if (dev == NULL)
        return NULL;

    nt = dev->priv;
    SET_MODULE_OWNER(dev);
    dev->init = ipip_tunnel_init;
    nt->parms = *parms;

    if (register_netdevice(dev) < 0) {
        free_netdev(dev);
        goto failed;
    }

    dev_hold(dev);
    ipip_tunnel_link(nt);
    return nt;

failed:
    return NULL;
}

int register_vlan_dev(struct net_device *dev)
{
	struct vlan_dev_info *vlan = vlan_dev_info(dev);
	struct net_device *real_dev = vlan->real_dev;
	const struct net_device_ops *ops = real_dev->netdev_ops;
	u16 vlan_id = vlan->vlan_id;
	struct vlan_group *grp, *ngrp = NULL;
	int err;

	grp = rtnl_dereference(real_dev->vlgrp);
	if (!grp) {
		ngrp = grp = vlan_group_alloc(real_dev);
		if (!grp)
			return -ENOBUFS;
		err = vlan_gvrp_init_applicant(real_dev);
		if (err < 0)
			goto out_free_group;
	}

	err = vlan_group_prealloc_vid(grp, vlan_id);
	if (err < 0)
		goto out_uninit_applicant;

	err = register_netdevice(dev);
	if (err < 0)
		goto out_uninit_applicant;

	/* Account for reference in struct vlan_dev_info */
	dev_hold(real_dev);

	netif_stacked_transfer_operstate(real_dev, dev);
	linkwatch_fire_event(dev); /* _MUST_ call rfc2863_policy() */

	/* So, got the sucker initialized, now lets place
	 * it into our local structure.
	 */
	vlan_group_set_device(grp, vlan_id, dev);
	grp->nr_vlans++;

	if (ngrp) {
		if (ops->ndo_vlan_rx_register)
			ops->ndo_vlan_rx_register(real_dev, ngrp);
		rcu_assign_pointer(real_dev->vlgrp, ngrp);
	}
	if (real_dev->features & NETIF_F_HW_VLAN_FILTER)
		ops->ndo_vlan_rx_add_vid(real_dev, vlan_id);

	return 0;

out_uninit_applicant:
	if (ngrp)
		vlan_gvrp_uninit_applicant(real_dev);
out_free_group:
	if (ngrp) {
		/* Free the group, after all cpu's are done. */
		call_rcu(&ngrp->rcu, vlan_rcu_free);
	}
	return err;
}

static int pim6_rcv(struct sk_buff *skb)
{
	struct pimreghdr *pim;
	struct ipv6hdr   *encap;
	struct net_device  *reg_dev = NULL;
	struct net *net = dev_net(skb->dev);
	int reg_vif_num = net->ipv6.mroute_reg_vif_num;

	if (!pskb_may_pull(skb, sizeof(*pim) + sizeof(*encap)))
		goto drop;

	pim = (struct pimreghdr *)skb_transport_header(skb);
	if (pim->type != ((PIM_VERSION << 4) | PIM_REGISTER) ||
	    (pim->flags & PIM_NULL_REGISTER) ||
	    (csum_ipv6_magic(&ipv6_hdr(skb)->saddr, &ipv6_hdr(skb)->daddr,
			     sizeof(*pim), IPPROTO_PIM,
			     csum_partial((void *)pim, sizeof(*pim), 0)) &&
	     csum_fold(skb_checksum(skb, 0, skb->len, 0))))
		goto drop;

	/* check if the inner packet is destined to mcast group */
	encap = (struct ipv6hdr *)(skb_transport_header(skb) +
				   sizeof(*pim));

	if (!ipv6_addr_is_multicast(&encap->daddr) ||
	    encap->payload_len == 0 ||
	    ntohs(encap->payload_len) + sizeof(*pim) > skb->len)
		goto drop;

	read_lock(&mrt_lock);
	if (reg_vif_num >= 0)
		reg_dev = net->ipv6.vif6_table[reg_vif_num].dev;
	if (reg_dev)
		dev_hold(reg_dev);
	read_unlock(&mrt_lock);

	if (reg_dev == NULL)
		goto drop;

	skb->mac_header = skb->network_header;
	skb_pull(skb, (u8 *)encap - skb->data);
	skb_reset_network_header(skb);
	skb->dev = reg_dev;
	skb->protocol = htons(ETH_P_IPV6);
	skb->ip_summed = 0;
	skb->pkt_type = PACKET_HOST;
	skb_dst_drop(skb);
	reg_dev->stats.rx_bytes += skb->len;
	reg_dev->stats.rx_packets++;
	nf_reset(skb);
	netif_rx(skb);
	dev_put(reg_dev);
	return 0;
 drop:
	kfree_skb(skb);
	return 0;
}

static int
ip6ip6_fb_tnl_dev_init(struct net_device *dev)
{
	struct ip6_tnl *t = netdev_priv(dev);
	ip6ip6_tnl_dev_init_gen(dev);
	dev_hold(dev);
	tnls_wc[0] = t;
	return 0;
}

void __netdev_watchdog_up(struct net_device *dev)
{
	if (dev->tx_timeout) {
		if (dev->watchdog_timeo <= 0)
			dev->watchdog_timeo = 5*HZ;
		if (!mod_timer(&dev->watchdog_timer, jiffies + dev->watchdog_timeo))
			dev_hold(dev);
	}
}

int ipv6_sock_mc_join(struct sock *sk, int ifindex, struct in6_addr *addr)
{
	struct net_device *dev = NULL;
	struct ipv6_mc_socklist *mc_lst;
	struct ipv6_pinfo *np = &sk->net_pinfo.af_inet6;
	int err;

	if (!(ipv6_addr_type(addr) & IPV6_ADDR_MULTICAST))
		return -EINVAL;

	mc_lst = sock_kmalloc(sk, sizeof(struct ipv6_mc_socklist), GFP_KERNEL);

	if (mc_lst == NULL)
		return -ENOMEM;

	mc_lst->next = NULL;
	memcpy(&mc_lst->addr, addr, sizeof(struct in6_addr));
	mc_lst->ifindex = ifindex;

	if (ifindex == 0) {
		struct rt6_info *rt;
		rt = rt6_lookup(addr, NULL, 0, 0);
		if (rt) {
			dev = rt->rt6i_dev;
			dev_hold(dev);
			dst_release(&rt->u.dst);
		}
	} else
		dev = dev_get_by_index(ifindex);

	if (dev == NULL) {
		sock_kfree_s(sk, mc_lst, sizeof(*mc_lst));
		return -ENODEV;
	}

	/*
	 *	now add/increase the group membership on the device
	 */

	err = ipv6_dev_mc_inc(dev, addr);

	if (err) {
		sock_kfree_s(sk, mc_lst, sizeof(*mc_lst));
		dev_put(dev);
		return err;
	}

	write_lock_bh(&ipv6_sk_mc_lock);
	mc_lst->next = np->ipv6_mc_list;
	np->ipv6_mc_list = mc_lst;
	write_unlock_bh(&ipv6_sk_mc_lock);

	dev_put(dev);

	return 0;
}

void __netdev_watchdog_up(struct net_device *dev)
{
	if (dev->netdev_ops->ndo_tx_timeout) {
		if (dev->watchdog_timeo <= 0)
			dev->watchdog_timeo = 5*HZ;
		if (!mod_timer(&dev->watchdog_timer,
			       round_jiffies(jiffies + dev->watchdog_timeo)))
			dev_hold(dev);
	}
}

static struct ip_tunnel * ipip6_tunnel_locate(struct net *net,
		struct ip_tunnel_parm *parms, int create)
{
	__be32 remote = parms->iph.daddr;
	__be32 local = parms->iph.saddr;
	struct ip_tunnel *t, **tp, *nt;
	struct net_device *dev;
	char name[IFNAMSIZ];
	struct sit_net *sitn = net_generic(net, sit_net_id);

	for (tp = __ipip6_bucket(sitn, parms); (t = *tp) != NULL; tp = &t->next) {
		if (local == t->parms.iph.saddr && remote == t->parms.iph.daddr)
			return t;
	}
	if (!create)
		goto failed;

	if (parms->name[0])
		strlcpy(name, parms->name, IFNAMSIZ);
	else
		sprintf(name, "sit%%d");

	dev = alloc_netdev(sizeof(*t), name, ipip6_tunnel_setup);
	if (dev == NULL)
		return NULL;

	dev_net_set(dev, net);

	if (strchr(name, '%')) {
		if (dev_alloc_name(dev, name) < 0)
			goto failed_free;
	}

	nt = netdev_priv(dev);

	nt->parms = *parms;
	ipip6_tunnel_init(dev);
	ipip6_tunnel_clone_6rd(dev, sitn);

	if (parms->i_flags & SIT_ISATAP)
		dev->priv_flags |= IFF_ISATAP;

	if (register_netdevice(dev) < 0)
		goto failed_free;

	dev_hold(dev);

	ipip6_tunnel_link(sitn, nt);
	return nt;

failed_free:
	free_netdev(dev);
failed:
	return NULL;
}

int xfrm_dev_state_add(struct net *net, struct xfrm_state *x,
		       struct xfrm_user_offload *xuo)
{
	int err;
	struct dst_entry *dst;
	struct net_device *dev;
	struct xfrm_state_offload *xso = &x->xso;
	xfrm_address_t *saddr;
	xfrm_address_t *daddr;

	if (!x->type_offload)
		return -EINVAL;

	/* We don't yet support UDP encapsulation, TFC padding and ESN. */
	if (x->encap || x->tfcpad || (x->props.flags & XFRM_STATE_ESN))
		return 0;

	dev = dev_get_by_index(net, xuo->ifindex);
	if (!dev) {
		if (!(xuo->flags & XFRM_OFFLOAD_INBOUND)) {
			saddr = &x->props.saddr;
			daddr = &x->id.daddr;
		} else {
			saddr = &x->id.daddr;
			daddr = &x->props.saddr;
		}

		dst = __xfrm_dst_lookup(net, 0, 0, saddr, daddr,
					x->props.family, x->props.output_mark);
		if (IS_ERR(dst))
			return 0;

		dev = dst->dev;

		dev_hold(dev);
		dst_release(dst);
	}

	if (!dev->xfrmdev_ops || !dev->xfrmdev_ops->xdo_dev_state_add) {
		dev_put(dev);
		return 0;
	}

	xso->dev = dev;
	xso->num_exthdrs = 1;
	xso->flags = xuo->flags;

	err = dev->xfrmdev_ops->xdo_dev_state_add(x);
	if (err) {
		dev_put(dev);
		return err;
	}

	return 0;
}

static void ip6_fb_tnl_dev_init(struct net_device *dev)
{
	struct ip6_tnl *t = netdev_priv(dev);
	struct net *net = dev_net(dev);
	struct ip6_tnl_net *ip6n = net_generic(net, ip6_tnl_net_id);

	ip6_tnl_dev_init_gen(dev);
	t->parms.proto = IPPROTO_IPV6;
	dev_hold(dev);
	ip6n->tnls_wc[0] = t;
}

static int pim6_rcv(struct sk_buff *skb)
{
	struct pimreghdr *pim;
	struct ipv6hdr   *encap;
	struct net_device  *reg_dev = NULL;

	if (!pskb_may_pull(skb, sizeof(*pim) + sizeof(*encap)))
		goto drop;

	pim = (struct pimreghdr *)skb_transport_header(skb);
	if (pim->type != ((PIM_VERSION << 4) | PIM_REGISTER) ||
	    (pim->flags & PIM_NULL_REGISTER) ||
	    (ip_compute_csum((void *)pim, sizeof(*pim)) != 0 &&
	     csum_fold(skb_checksum(skb, 0, skb->len, 0))))
		goto drop;

	/* check if the inner packet is destined to mcast group */
	encap = (struct ipv6hdr *)(skb_transport_header(skb) +
				   sizeof(*pim));

	if (!ipv6_addr_is_multicast(&encap->daddr) ||
	    encap->payload_len == 0 ||
	    ntohs(encap->payload_len) + sizeof(*pim) > skb->len)
		goto drop;

	read_lock(&mrt_lock);
	if (reg_vif_num >= 0)
		reg_dev = vif6_table[reg_vif_num].dev;
	if (reg_dev)
		dev_hold(reg_dev);
	read_unlock(&mrt_lock);

	if (reg_dev == NULL)
		goto drop;

	skb->mac_header = skb->network_header;
	skb_pull(skb, (u8 *)encap - skb->data);
	skb_reset_network_header(skb);
	skb->dev = reg_dev;
	skb->protocol = htons(ETH_P_IP);
	skb->ip_summed = 0;
	skb->pkt_type = PACKET_HOST;
	dst_release(skb->dst);
	((struct net_device_stats *)netdev_priv(reg_dev))->rx_bytes += skb->len;
	((struct net_device_stats *)netdev_priv(reg_dev))->rx_packets++;
	skb->dst = NULL;
	nf_reset(skb);
	netif_rx(skb);
	dev_put(reg_dev);
	return 0;
 drop:
	kfree_skb(skb);
	return 0;
}

static void linkwatch_add_event(struct net_device *dev)
{
	unsigned long flags;

	spin_lock_irqsave(&lweventlist_lock, flags);
	if (list_empty(&dev->link_watch_list)) {
		list_add_tail(&dev->link_watch_list, &lweventlist);
		dev_hold(dev);
	}
	spin_unlock_irqrestore(&lweventlist_lock, flags);
}

static struct net_device *rxe_get_netdev(struct ib_device *device,
					 u8 port_num)
{
	struct rxe_dev *rxe = to_rdev(device);

	if (rxe->ndev) {
		dev_hold(rxe->ndev);
		return rxe->ndev;
	}

	return NULL;
}

int register_vlan_dev(struct net_device *dev)
{
	struct vlan_dev_priv *vlan = vlan_dev_priv(dev);
	struct net_device *real_dev = vlan->real_dev;
	u16 vlan_id = vlan->vlan_id;
	struct vlan_info *vlan_info;
	struct vlan_group *grp;
	int err;

	err = vlan_vid_add(real_dev, vlan_id);
	if (err)
		return err;

	vlan_info = rtnl_dereference(real_dev->vlan_info);
	/* vlan_info should be there now. vlan_vid_add took care of it */
	BUG_ON(!vlan_info);

	grp = &vlan_info->grp;
	if (grp->nr_vlan_devs == 0) {
		err = vlan_gvrp_init_applicant(real_dev);
		if (err < 0)
			goto out_vid_del;
	}

	err = vlan_group_prealloc_vid(grp, vlan_id);
	if (err < 0)
		goto out_uninit_applicant;

	err = register_netdevice(dev);
	if (err < 0)
		goto out_uninit_applicant;

	/* Account for reference in struct vlan_dev_priv */
	dev_hold(real_dev);

	netif_stacked_transfer_operstate(real_dev, dev);
	linkwatch_fire_event(dev); /* _MUST_ call rfc2863_policy() */

	/* So, got the sucker initialized, now lets place
	 * it into our local structure.
	 */
	vlan_group_set_device(grp, vlan_id, dev);
	grp->nr_vlan_devs++;

	return 0;

out_uninit_applicant:
	if (grp->nr_vlan_devs == 0)
		vlan_gvrp_uninit_applicant(real_dev);
out_vid_del:
	vlan_vid_del(real_dev, vlan_id);
	return err;
}

/* Dirty hack. We did it in 2.2 (in __dst_free),
 * we have _very_ good reasons not to repeat
 * this mistake in 2.3, but we have no choice
 * now. _It_ _is_ _explicit_ _deliberate_
 * _race_ _condition_.
 *
 * Commented and originally written by Alexey.
 */
static void dst_ifdown(struct dst_entry *dst, struct net_device *dev,
		       int unregister)
{
	if (dst->ops->ifdown)
		dst->ops->ifdown(dst, dev, unregister);

	if (dev != dst->dev)
		return;

	if (!unregister) {
		dst->input = dst->output = dst_discard;
	} else {
		dst->dev = dev_net(dst->dev)->loopback_dev;
		dev_hold(dst->dev);
		dev_put(dev);
		if (dst->neighbour && dst->neighbour->dev == dev) {
			dst->neighbour->dev = dst->dev;
			dev_hold(dst->dev);
			dev_put(dev);
		}
	}
}

static struct net_device *qedr_get_netdev(struct ib_device *dev, u8 port_num)
{
	struct qedr_dev *qdev;

	qdev = get_qedr_dev(dev);
	dev_hold(qdev->ndev);

	/* The HW vendor's device driver must guarantee
	 * that this function returns NULL before the net device reaches
	 * NETDEV_UNREGISTER_FINAL state.
	 */
	return qdev->ndev;
}

/* Create a child dst_entry with locked interface MTU, and attach it to `dst'. 
   This is needed on newer linux kernels and IP_ONLY_INTERCEPTOR builds,
   where the IP stack fragments packets to path MTU after ssh_interceptor_send.
*/
static struct dst_entry * 
interceptor_route_create_child_dst(struct dst_entry *dst)
{
  struct dst_entry *child;

  /* Allocate a dst_entry and copy relevant fields from dst. */
  child = dst_alloc(dst->ops);
  if (child == NULL)
    return NULL;
  
  child->input = dst->input;
  child->output = dst->output;
  
  /* Child is not added to dst hash, and linux native IPsec is disabled. */
  child->flags |= (DST_NOHASH | DST_NOPOLICY | DST_NOXFRM);
  
  /* Copy route metrics and lock MTU to interface MTU. */
  memcpy(child->metrics, dst->metrics, sizeof(child->metrics));
  child->metrics[RTAX_LOCK-1] |= 1 << RTAX_MTU;
  
#ifdef CONFIG_NET_CLS_ROUTE  
  child->tclassid = dst->tclassid;
#endif /* CONFIG_NET_CLS_ROUTE */
  
  child->xfrm = NULL;
  
  if (dst->hh)
    {
      atomic_inc(&dst->hh->hh_refcnt);
      child->hh = dst->hh;
    }

  if (dst->neighbour)
    {
      child->neighbour = neigh_clone(dst->neighbour);
    }

  if (dst->dev)
    {
      dev_hold(dst->dev);
      child->dev = dst->dev;
    }

  SSH_ASSERT(dst->child == NULL);
  dst->child = dst_clone(child);
  
  SSH_DEBUG(SSH_D_MIDOK, ("Allocated child %p dst_entry for dst %p mtu %d",
			  child, dst, dst_mtu(dst)));

  return child;
}

/*
 * sfe_cm_find_dev_and_mac_addr()
 *	Find the device and MAC address for a given IPv4 address.
 *
 * Returns true if we find the device and MAC address, otherwise false.
 *
 * We look up the rtable entry for the address and, from its neighbour
 * structure, obtain the hardware address.  This means this function also
 * works if the neighbours are routers too.
 */
static bool sfe_cm_find_dev_and_mac_addr(uint32_t addr, struct net_device **dev, uint8_t *mac_addr)
{
	struct neighbour *neigh;
	struct rtable *rt;
	struct dst_entry *dst;
	struct net_device *mac_dev;

	/*
	 * Look up the rtable entry for the IP address then get the hardware
	 * address from its neighbour structure.  This means this work when the
	 * neighbours are routers too.
	 */
	rt = ip_route_output(&init_net, addr, 0, 0, 0);
	if (unlikely(IS_ERR(rt))) {
		return false;
	}

	dst = (struct dst_entry *)rt;

	rcu_read_lock();
	neigh = dst_get_neighbour_noref(dst);
	if (unlikely(!neigh)) {
		rcu_read_unlock();
		dst_release(dst);
		return false; 
	}

	if (unlikely(!(neigh->nud_state & NUD_VALID))) {
		rcu_read_unlock();
		dst_release(dst);
		return false;
	}

	mac_dev = neigh->dev;
	if (!mac_dev) {
		rcu_read_unlock();
		dst_release(dst);
		return false;
	}

	memcpy(mac_addr, neigh->ha, (size_t)mac_dev->addr_len);

	dev_hold(mac_dev);
	*dev = mac_dev;
	rcu_read_unlock();

	dst_release(dst);

	return true;
}

/* Some devices are known to send Neigbor Solicitation messages and
 * require Neigbor Advertisement replies.  The IPv6 core will not
 * respond since IFF_NOARP is set, so we must handle them ourselves.
 */
static void do_neigh_solicit(struct usbnet *dev, u8 *buf, u16 tci)
{
	struct ipv6hdr *iph = (void *)buf;
	struct nd_msg *msg = (void *)(iph + 1);
	struct net_device *netdev;
	struct inet6_dev *in6_dev;
	bool is_router;

	/* we'll only respond to requests from unicast addresses to
	 * our solicited node addresses.
	 */
	if (!ipv6_addr_is_solict_mult(&iph->daddr) ||
	    !(ipv6_addr_type(&iph->saddr) & IPV6_ADDR_UNICAST))
		return;

	/* need to send the NA on the VLAN dev, if any */
	rcu_read_lock();
	if (tci) {
		netdev = __vlan_find_dev_deep_rcu(dev->net, htons(ETH_P_8021Q),
						  tci);
		if (!netdev) {
			rcu_read_unlock();
			return;
		}
	} else {
		netdev = dev->net;
	}
	dev_hold(netdev);
	rcu_read_unlock();

	in6_dev = in6_dev_get(netdev);
	if (!in6_dev)
		goto out;
	is_router = !!in6_dev->cnf.forwarding;
	in6_dev_put(in6_dev);

	/* ipv6_stub != NULL if in6_dev_get returned an inet6_dev */
#if LINUX_VERSION_CODE >= KERNEL_VERSION(4,4,0)
	ipv6_stub->ndisc_send_na(netdev, &iph->saddr, &msg->target,
				 is_router /* router */,
				 true /* solicited */,
				 false /* override */,
				 true /* inc_opt */);
#else
	ipv6_stub->ndisc_send_na(netdev, NULL, &iph->saddr, &msg->target,
				 is_router, true, false, true);
#endif
out:
	dev_put(netdev);
}